STMicroelectronics STSW-ST25DV002 User Manual
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UM2949
User manual
STSW-ST25DV002 firmware for the ST25DV64KC-DISCO board
Introduction
This document describes the functionalities of the STSW-ST25DV002 firmware, developed to take full advantage of the
ST25DV64KC-DISCO board functionalities, working with any dynamic tag of the ST25DV-I2C Series.
In this document, the dynamic tag series from STMicroelecronics is referred to as ST25DV-I2C tags.
The ST25DV-I2C tags are integrated circuits (IC) for contactless applications that communicate with a microcontroller through an I 2 C interface; this makes this device a dynamic tag. On the RF side, the reader (for instance a smart phone) retrieves and updates the content of the tag when close by.
The reader communicates with the ST25DV64KC-DISCO board using the ISO 15693 protocol, while the STM32L476xx microcontroller device communicates with the ST25DV-I2C tag through an I 2 C bus.
With this discovery kit, the ST25DV-I2C tag is ready to receive any content, following the NFC Forum standard. This means that a smart phone is able to natively read it, without having previously installed any specific application.
A specific Fast transfer mode allows the user to transfer data directly to the microcontroller, without using the embedded
EEPROM.
UM2949 - Rev 1 - February 2022
For further information contact your local STMicroelectronics sales office.
www.st.com
1
Note:
General information
This document applies to the STM32L476xx Arm ® -based microcontroller devices.
Arm is a registered trademark of Arm Limited (or its subsidiaries) in the US and/or elsewhere.
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General information
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2
2.1
2.2
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List of acronyms and notational conventions
List of acronyms and notational conventions
List of acronyms
APB
AAR
NFC
OOB
R2H
RF
RFID
RISC
SPI
URI
URL
USB
BLE
CAN
GPS
GPO
H2R
IEC
ISO
MCU
Acronym
Table 1. Acronyms
Definition
Advanced peripheral bus
Android ™ application record
Bluetooth ® Low Energy
Controller area network
Global positioning system
General purpose output
Host to reader
International electrotechnical commission
International standards organization
Micro controller unit (microcontroller)
Near field communication
Out of band
Reader to host
Radio frequency
Radio frequency identification
Reduced instruction set computer
Serial peripheral interface
Uniform resource identifier
Uniform resource locator
Universal serial bus
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Number convention and notation
The following conventions and notations apply in this document unless otherwise stated:
Binary numbers are represented by strings of 0 and 1 digits starting with the most significant bit (MSB) on the left followed by the least significant bit (LSB) on the right, and "0b" added at the beginning. Example:
0b11110101.
Hexadecimal numbers are represented by using numbers 0 to 9 and characters A to F, and adding "0x" at the beginning. The MSB is shown on the left and the LSB on the right. Example: 0xF5.
Decimal numbers are represented without any leading character. Example: 245.
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3
3.1
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Overview
Overview
ST25DV-I2C tag
The ST25DV-I2C tag is a dynamic tag IC for contactless applications (ISO 15693). It manages the RF communication with a reader. It also includes frame coding, RF modulation and manages the anti-collision process.
The ST25DV-I2C tag works as an NFC Forum Type 5 tag, supporting: detection, read and write operations. As shown in
, this device communicates with a reader without any external controller.
Figure 1. Communication scheme
MCU
I 2 C
ST25DV-I2C RF
3.2
STM32L476xx microcontroller devices
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The STM32L476xx microcontroller devices are ultra-low-power microcontrollers based on the high-performance
Arm ® 32-bit RISC core operating at a frequency of up to 80 MHz. The Arm ® Cortex ® -M4 core features a floating point unit (FPU) single precision, which supports all Arm ® single-precision data-processing instructions and data types. It also implements a full set of DSP instructions and a memory protection unit (MPU) to enhance application security.
The STM32L476xx microcontroller devices embed high-speed memories (up to 1 Mbytes of Flash memory, up to 128 Kbytes of SRAM), a flexible external memory controller (FSMC) for static memories (for devices with packages of 100 pins and more), a Quad-SPI Flash memory interface (available on all packages) and an extensive range of enhanced I/Os and peripherals connected to two APB buses, two AHB buses and a 32-bit multi-AHB bus matrix.
The STM32L476xx microcontroller devices embed several protection mechanisms for embedded Flash memory and SRAM: readout protection, write protection, proprietary code readout protection and firewall.
•
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These devices offer up to three fast 12-bit ADCs (5 Msps), two comparators, two operational amplifiers, two
DAC channels, an internal voltage reference buffer, a low-power RTC, two general-purpose 32-bit timers, two
16-bit PWM timers dedicated to motor control, seven general-purpose 16-bit timers, and two 16-bit low-power timers. The STM32L476xx microcontroller devices support four digital filters for external sigma delta modulators
(DFSDM).
In addition, up to 24 capacitive sensing channels are available. The devices also embed an integrated LCD driver
8x40 or 4x44, with internal step-up converter.
They also feature standard and advanced communication interfaces:
Three I²Cs
Three SPIs
Three USARTs, two UARTs and one Low-power UART.
Two SAIs (serial audio interfaces)
One SDMMC
One CAN
One USB OTG full-speed
One SWPMI (single wire protocol master interface)
For full details of the STM32L476xx microcontroller device specifications, refer to www.st.com
.
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3.3
3.3.1
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ST25DV64KC-DISCO boards
ST25DV64KC-DISCO boards
The ST25DV64KC-DISCO is an evaluation kit, which allows the user to evaluate the performance of the ST25DV-
I2C tag dynamic tag. The kit is composed of two boards, namely a motherboard (see
) and the ST25DV-
I2C tag daughter board (see Figure 3 ).
ST25DV64KC-DISCO motherboard
The ST25DV64KC-DISCO (illustrated in
) is powered through the USB bus (micro and mini connectors) and no external power supply is required.
This motherboard embeds the STM32L476VG microcontroller and different peripherals:
•
•
LCD display and touchscreen to interface with the user
USB connectors to connect to a PC (mini-USB for the ST-Link debugger and micro-USB available for the user application)
• Optional modules: Wi ‑ Fi ® and BLE to connect with a smart phone
The connectors on the right side of the board are dedicated to the daughter boards that embed the NFC tags.
Figure 2. ST25DV64KC-DISCO motherboard MB1396
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3.3.2
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ST25DV64KC-DISCO boards
ST25DV-I2C tag daughter board
The ST25DVKC Discovery ANT C3 board (illustrated in
) embeds the ST25DV64KC device and a 40 mm x 23 mm, 13.56 MHz double layer inductive etched antenna (no need for any tuning components).
The ST25DV64KC communicates with the STM32L476VG 32-bit MCU via the I²C bus.
Figure 3. ST25DVKC Discovery ANT C3 board
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4
4.1
4.2
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Firmware description
Firmware description
Prerequisite
The ST25DV-I2C tag is a dynamic tag, whose content and configuration is driven by both a microcontroller
(through I²C) and a reader through RF.
To benefit from the ST25DV64KC-DISCO demonstration kit, the user must have one of the following:
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A smart phone with the NFC enabled, combined with the ST25 NFC App installed on it. Refer to ST25
Android ™ NFC tap application (UM2131), available on www.st.com
for more information.
An NFC reader, such as the CR95HF distributed with the M24LR discovery kit (M24LR-DISCOVERY). To take full advantage of the ST25DV-I2C tag features, use CR95HF transceiver board firmware version 3.7.0
or higher, combined with the ST25PC-NFC software. Refer to Software toolbox for NFC tags user manual
(UM2444), available on www.st.com
.
The ST25DV-I2C tag is fully compliant with the NFC Forum Type 5 standard. As this standard is recently introduced, some features may not be fully supported by older smart phones.
Main menu
The main menu (
) is composed of three icons, used to access sub-menus.
Figure 4. ST25DV64KC-DISCO main menu display
Each item allows the user to enter a sub-menu containing a set of use cases as outlined. The sub-menus are
Discover ST25DV-I2C tag
Table 2. Main menu item definition
Fast transfer mode demonstration NFC NDEF demonstrations
Note: If the Wi ‑ Fi ® and/or the Bluetooth ® Low Energy modules have been added to the board, the corresponding icons are available to access the Wi ‑ Fi ® and Bluetooth ® pairing demonstrations.
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4.2.1
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Main menu
To select a category, touch the icon on the screen. To start a demonstration, touch the desired demonstration icon on the screen (see description below). A long touch on an icon displays the description of the corresponding demonstration(s) in the top line.
As the purpose of this document is to illustrate the firmware behavior, the descriptions are detailed from the microcontroller point of view.
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Discover ST25DV-I2C tag menu
tag specific features, among them:
GPO interrupts in
Energy harvesting in
ST25DV-I2C tag states in
Multi-areas and passwords in Section 4.2.5
Figure 5. ST25DV64KC-DISCO features main display
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4.2.2
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Main menu
RF GPO interrupt demonstration
The ST25DV-I2C tag has a GPO that is used to send interrupts to the microcontroller.
Several kinds of event on the RF side may be configured to trigger the GPO interrupt. In this demonstration all possible interrupt sources are enabled, except for the "RF activity", which occurs too often for reasonable readability when using a smart phone as a reader.
To start the demonstration, select the "GPO control demo" menu, this displays the instructions until it detects a
GPO interrupt.
As soon as the first GPO interrupt is received, the LCD displays the list of sources of received interrupt, and the number of each interrupt occurrences (see
).
Figure 6. ST25DV64KC-DISCO interrupt generation display
Note:
The event types and the way to generate them are listed below:
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Field on: place a reader near the ST25DV-I2C tag
Field off: move a reader away from the ST25DV-I2C tag
EEPROM written: modify the content of the ST25DV-I2C tag
RF interrupt: requires the use of a specific reader instruction, that is sent either by a smart phone running
the ST25 NFC app, or by a reader (see the instructions in Smart phone GPO management and
Generating the RF and RF user interrupts using the ST25PC-NFC software with the CR95HF
sections, respectively, for
Android ™ ST25 NFC application and for the CR95HF reader used with the ST25PC-NFC software)
RF user: requires the use of a specific reader command, that is sent either by a smart phone running the
ST25 NFC app or by a reader (see the instructions in Smart phone GPO management and
Android ™ ST25 NFC application and for the CR95HF reader used with the ST25PC-NFC software)
To start the Android ST25 NFC application, read the ST25DV-I2C tag with a smart phone (after entering the GPO demonstration), which automatically opens the required application (or propose the installation of the application).
The automatic application selection is done using an NDEF with an AAR.
The mailbox events are also used to trigger the GPO interrupts. They are not mentioned here, as they would require placing the ST25DV-I2C tag in the Mailbox mode.
Smart phone GPO management
The ST25 NFC application handles the RF interrupt and the RF user interrupt using register fields information
(see
). Do not forget to present the configuration password before any register change.
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Figure 7. Smart phone GPO register configuration
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Main menu
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The ST25 NFC application generates the RF interrupt and the RF user interrupt using features located in the
Tools fragment in association with the RF GPO interrupt demonstration.
Generating the RF and RF user interrupts using the ST25PC-NFC software with the CR95HF
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These interrupts are generated by any RF reader or Android ™ smart phone.
Using the CR95HF IC and ST25PC-NFC software, the user is able to send interrupts or drive the GPO (see
Select the ST25DV-I2C tag product
Select "ENERGY HARVESTING" and GPO tab
Click on "Send Interrupt Generated by GPO" to send an interrupt on GPO line
Click on GPO set or GPO reset to be able to drive the GPO line.
For additional information about CR95HF PC software refer to the CR95HF development software user manual
(UM1084), available on www.st.com
.
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Figure 8. ST25DV-I2C tag contextual menu
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Main menu
Figure 9. PC software ST25DV-I2C tag special commands interface page 11/60
4.2.3
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Main menu
ST25DV-I2C tag energy harvesting demonstration
The ST25DV-I2C is able to harvest the energy provided by the RF to power other devices.
This demonstration displays the voltage, current and power provided by the ST25DV-I2C (see
Figure 10. ST25DV64KC-DISCO energy harvesting measurement display
A LED is also turned on to simulate the effect of the energy harvesting when the RF field is approaching or when it leaves.
The energy harvesting pin is connected to a load with which is used to measure the current delivered by the tag.
This load is configurable (shown in
Figure 10 ) from 540 Ω to 4320 Ω. The objective is to simulate the current
consumed by additional external circuitry.
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4.2.4
Note:
4.2.5
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Main menu
ST25DV-I2C tag states demonstration
This menu illustrates the possibility to change the ST25DV-I2C tag state, for example the power save demonstration. This demonstration proposes three different modes:
1.
RF disabled mode: RF commands are interpreted but not executed. The ST25DV-I2C tag responds with the error code 0x0F.
2.
Sleep mode: all RF communications are disabled, the RF interface does not interpret the commands, but minimizes consumption of RF interface.
3.
Low-power down: the ST25DV-I2C tag is fully inactive from Host - I 2 C side, but the memory content is accessible on the RF side.
For all above cases, the demonstration consists in writing an NDEF with the ST25 URL, and changing the
ST25DV-I2C tag state. A message is displayed that invites the user to try to read the content of the ST25DV-I2C tag, and check that it is not possible.
The content of the ST25DV-I2C tag can be read again as soon as the demonstration screen is passed.
For the Low-power mode, the ST25DXSPARE jumper must be present on the ST25DV64KC-DISCO board's
MCU pin, and a 12-pin package must be used for the ST25DV-I2C tag.
ST25DV-I2C tag multi area and password demonstration
The ST25DV-I2C tag defines up to four different areas in memory. Each area may have a custom security level, requiring one of the three passwords to be provided in order to read and/or write the memory.
This demonstration sets two different areas:
1.
"Area 1" contains an NDEF with a vCard. This area is readable by anyone, but can only be written after presenting "password 1".
2.
"Area 2" contains an NDEF with a different vCard. This area cannot be read without the "password 1", and cannot be written even after the password presentation.
By default, all the passwords are set to 0000 0000 0000 0000. These values are only updated from the RF side.
To execute the demonstration, the user must first read the ST25DV-I2C tag without any specific application. The phone displays the vCard stored in "Area 1".
Then the user opens the ST25 NFC application, and taps the tag again, the application detects two areas, and displays the "Area "1 vCard.
The user may try to write a different NDEF to the "Area 1", and check that the write fails unless "password 1" is presented.
If the user selects the "Area 2" NDEF, the application requests "password 1" before displaying the "Area 2" vCard.
The user may try to write a different NDEF in "Area 2", this does not work even after presenting "password 1".
This is expected, as the security level of "Area 2" prevents any write access to the memory.
Smart phone and multi areas
When the tag is configured in multi areas, the ST25 NFC application then handles the areas and presents areas and content to the user. The user then chooses the desired area by selecting the corresponding menu in the application drawer. This is illustrated in
In case special protection is needed, the application displays security status information. On click, a popup is used to present the area password needed to access area content.
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Figure 11. Smart phone and area display
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Main menu
ST25PC-NFC software and multi areas
The ST25PC-NFC software is used to create up to four areas on the ST25DV-I2C tag EEPROM:
1.
From the Inventory side panel, right-click on the ST25DV-I2C tag tag (see Figure 8 ).
2.
In the contextual menu, select the "Multi Area Editor" item.
3.
Move the sliders for each area until the desired value is reached (see Figure 12
for an example of an
EEPROM cut into four equal areas of 2048 bytes segments).
4.
The start address, size of the area and ENDA register values are updated in real time inside the bottom table.
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Main menu
Figure 12. ST25DV-I2C tag multi area configuration interface of the ST25PC-NFC software
Access rights for each area of the tag are set from the "Area configuration" screen (see
1.
From the table, select the area to protect (up to four areas).
2.
In the "Area protection" column, set one of four options for read and write operations (only three are available for "Area 1").
3.
Additionally, the password number can be set for each area.
Figure 13. Area configuration interface of the ST25PC-NFC software page 15/60
4.2.6
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Main menu
ST25DV-I2C tag compare EEPROM write
This menu shows the difference between writing to the 4-byte ST25DVxxK EEPROM page and to the 16-byte
ST25DVxxKC EEPROM page. When entering this menu the following screens show the difference by emulating an ST25DVxxKC EEPROM page write and performing the actual write on the ST25DVxxKC EEPROM.
Figure 14. ST25DVxxK emulated EEPROM write screen
Figure 15. ST25DVxxK emulated EEPROM write results
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Figure 16. ST25DVxxKC EEPROM write screen
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Main menu
Figure 17. ST25DVxxKC EEPROM write results
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4.2.7
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Main menu
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NFC NDEF demonstration menu
The NFC NDEF demonstrations menu (see Figure 18
) proposes several demonstrations concerning NDEF messages:
URI NDEF message (URL and phone number)
SMS NDEF message
Email NDEF message vCard NDEF message
Geo-location NDEF message
Custom (MyApp) NDEF message
Multi record NDEF message
Bluetooth ® Low Energy OOB NDEF message (requires an additional Bluetooth ® Low Energy module)
Wi ‑ Fi ® OOB NDEF message (requires an additional Wi ‑ Fi ® module).
Figure 18. ST25DV64KC-DISCO NFC NDEF demonstrations menu display
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URI demonstration
This menu (see
Figure 19 ) shows how to manage URI content in the ST25DV-I2C tag.
With the MCU, the user:
•
•
Stores an NDEF message containing a URL or a phone number (it is then be read with an NFC reader or a smart phone).
Reads any URI that is stored in the ST25DV-I2C tag. The display shows the content of the URI.
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Figure 19. ST25DV64KC-DISCO read URI display
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Main menu
Note: If the MCU reads the ST25DV-I2C tag memory, it does not contain a URI, an error message is displayed.
Smart phone and URI NDEF
Refer to
Reading and writing NDEF on a smart phone with the Android ST25 application
section.
SMS demonstration
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This menu indicates how to manage SMS content in the ST25DV-I2C tag.
With the MCU, the user:
Stores an NDEF message containing an SMS (it is then be read with an NFC reader or with a smart phone)
Reads any SMS that is stored in the ST25DV-I2C tag memory (the SMS is displayed on the screen).
Figure 20. ST25DV64KC-DISCO read SMS content display
Note: If the MCU reads the ST25DV-I2C tag memory, it does not contain an SMS, an error message is displayed.
Smart phone and SMS NDEF
Refer to
Reading and writing NDEF on a smart phone with the Android ST25 application
section.
Email demonstration
The menu illustrated in Figure 21
indicates how to manage e-mail content in the ST25DV-I2C tag.
With the MCU, the user:
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•
Stores an NDEF message containing an e-mail (it is then be read with an NFC reader or with a smart phone).
Reads any e-mail that is stored in the ST25DV-I2C tag memory. The content of the e-mail is displayed on the screen.
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Figure 21. ST25DV64KC-DISCO read Email content display
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Main menu
Note:
Note:
If the MCU reads the ST25DV-I2C tag memory, it does not contain an e-mail, an error message is displayed.
Smart phone and e-mail NDEF
Refer to
Reading and writing NDEF on a smart phone with the Android ST25 application
section.
vCard demonstration
The menu illustrated in Figure 22
indicates how to manage vCard content in the ST25DV-I2C tag.
With the MCU, the user:
• Stores an NDEF message containing a vCard. Depending on the size of the ST25DV-I2C tag, this vCard may or may not embed a picture
Reads the ST25DV-I2C tag content.
•
If the vCard was previously stored, the following information is displayed on the board screen: name, title, organization, cell phone number, work address and work e-mail.
The vCard with an embedded picture needs around 3 Kbytes of memory and cannot be stored in the ST25DV-
I2C tag devices with smaller memory sizes, the ST25DV64 (with 64 kbits) must be used.
If the MCU reads the ST25DV-I2C tag memory, it does not contain a vCard, an error message is displayed.
Only vCard 2.1 is implemented in this firmware version. If the user stores a vCard 3.0 in the ST25DV-I2C tag, the firmware issues an error message.
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Figure 22. ST25DV64KC-DISCO read vCard content display
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Main menu
Smart phone and vCard NDEF
Refer to
Reading and writing NDEF on a smart phone with the Android ST25 application
section.
Geolocation demonstration
The menu illustrated in Figure 23
indicates how to manage the geolocation content in the ST25DV-I2C tag.
With the MCU, the user:
•
•
Stores an NDEF message containing a geolocation (it is then read with an NFC reader or with a smart phone)
Reads any geolocation that is stored in the ST25DV-I2C tag memory, the content is displayed on the screen.
Figure 23. ST25DV64KC-DISCO read geolocation display
Note: If the MCU reads the ST25DV-I2C tag memory, it does not contain a geolocation, an error message is displayed.
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Note:
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Main menu
MyApp record demonstration
This demonstration illustrated by
Figure 24 shows how to use a proprietary NDEF record to control an application
running on the host MCU. As the format of the message follows the NFC Forum NDEF standard, it is written or read by any device supporting this format.
The MCU waits until a "Proprietary configuration" record is written to the tag, then it updates the LCD display and controls a LED as described in the record.
•
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This demonstration uses the ST25DV-I2C tag GPO to detect that the ST25DV-I2C tag is written to. In the ST25
NFC App, the user must enter the "compose NDEF" menu, and then select the "Proprietary configuration" record.
From there, the user:
Selects whether the LED1 must blink and configure the blinking period.
Enters the text to be displayed by the MCU.
The "Proprietary configuration" record allows the user to control up to four LEDs. As the ST25DV64KC-DISCO board has only one LED, configuring LED2, LED3 or LED4 has no effect.
After changing the setting in the compose "Proprietary configuration" record menu, the user must click on "Write to tag" and tap the ST25DV-I2C tag. As soon as a new message is written in the ST25DV-I2C tag memory, the MCU reads it and if it finds the expected message, it configures the LED and the LCD as specified in the message.
If the data written to the ST25DV-I2C tag is not a valid "Proprietary configuration" record, the MCU displays an error message and continues waiting for a valid "Proprietary configuration" record to be written.
Figure 24. ST25DV64KC-DISCO MyApp demonstration screen
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Multi record demonstration
This menu indicates how to manage a multi record NDEF in the ST25DV-I2C tag.
With the MCU, the user:
•
•
Stores an NDEF message containing the ST25 URI (it is then be read with an NFC reader or a smart phone).
Adds the "ST25 Android ™ Application Record" (ST25 AAR) to the existing NDEF message.
For this demonstration, the user is requested to read the URI with a smart phone, and check that its preferred browser is open with the ST25 URL (this is the default behavior when URI is natively supported by the smart phone).
Then, after adding the ST25 AAR, when the ST25DV-I2C tag is read with a smart phone, the browser is no longer open, while the ST25 application is. The URI appears as the first record in the application.
Smart phone and multi records NDEF
This section provides dedicated indications how to build multi records NDEFs (see Figure 25
).
How to build each record:
1.
From "Ndef Editor" menu, click on the '+' at the bottom right corner to add a record. A popup appears allowing the user to choose the record type.
2.
Fill the record and click on the floppy icon, in the top right corner, to save the record to the tag.
3.
Proceed in the same way to add more records.
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Figure 25. Smart phone and multi records editor display
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Main menu
Note:
Bluetooth ® Low Energy pairing demonstration (requires an additional Bluetooth ® Low Energy module)
This menu indicates how to manage a Bluetooth ® Low Energy pairing content in the ST25DV-I2C tag. By default, the ST25DV64KC-DISCO board does not feature the Bluetooth ® Low Energy functionality, and is added using the
ST BlueNRG module.
For this demonstration, the user reads the ST25DV-I2C tag content with a smart phone having the Bluetooth ®
Low Energy OOB support (e.g. Android ™ 6.0).
With the MCU, the user:
•
•
Stores an NDEF message containing the Bluetooth ® Low Energy Out-Of-Band (OOB)
Reads a Bluetooth ® or Bluetooth ® Low Energy OOB previously stored in the ST25DV-I2C tag memory.
When the user reads the ST25DV-I2C tag with a smart phone having Bluetooth ® Low Energy support, the smart phone automatically asks confirmation and connects to the BlueNRG module present on the demonstration board. The MAC address provided by the smart phone is displayed on the screen of the demonstration board as soon as the pairing is completed.
The BlueNRG is configured to act as a human interface device (HID); it is displayed on the smart phone with this name: HID.
The HID protocol is natively supported by Android ™ 6.0 smart phones, and this demonstration allows the user to control a pointer on the paired phone, by touching the screen of the ST25DV64KC-DISCO board. The screen acts as a touch-pad, the user button as a select button.
Touch the bottom line of the LCD to exit this demonstration.
The user selects the "Change BLE Address" command to prevent spurious connections from previously paired smart phones.
This changes the Bluetooth ® Low Energy module device address, and is seen by smart phones as a different device (however the device name - HID - is left unchanged).
Some smart phones require a specific action from the user to enable the HID control (this setting may be located in the smart phone's Bluetooth
®
menu).
Smart phone and Bluetooth ® Low Energy
Refer to
Reading and writing NDEF on a smart phone with the Android ST25 application
section.
Wi ‑ Fi ® pairing demonstration (requires an additional Wi ‑ Fi ® module)
This menu indicates how to manage a Wi ‑ Fi ® pairing content in the ST25DV-I2C tag. By default, the
ST25DV64KC-DISCO board does not feature the Wi ‑ Fi ® module. To access this feature add the ST SPWF01 module which acts as a mini Wi ‑ Fi
®
access point.
For this demonstration, the ST25DV-I2C tag content is read with a smart phone using Wi ‑ Fi ® .
With the MCU, the user:
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Note:
Note:
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Main menu
•
•
Stores an NDEF message containing a Wi ‑ Fi ® protected setup (WPS) OOB descriptor.
Reads a WPS OOB previously stored in the ST25DV-I2C tag memory.
When the user reads the ST25DV-I2C tag with a smart phone having the Wi ‑ Fi automatically asks a confirmation and connects to the SWPF_AS01 Wi ‑ Fi ®
®
support, the smart phone
network. The MAC address provided by the smart phone is displayed on the screen of the demonstration board as soon as the connection is completed.
For the demonstration no Internet access is provided by the board mini access point.
If, when the MCU reads the ST25DV-I2C tag memory, it does not contain a WPS OOB, an error message is displayed.
Smart phone and Wi ‑ Fi ® pairing
Refer to
Reading and writing NDEF on a smart phone with the Android ST25 application
section.
Reading and writing NDEF on a smart phone with the Android ™ ST25 application
The ST25 NFC App enables to read or write NDEF messages.
•
•
Read: tap the tag, if a managed NDEF is discovered, content is accessible from the NDEF tab or NDEF editor (refer to the Android ™ application user manual for more details), see
Write an NDEF: select "NDEF editor" and choose the NDEF type has to be written. An editor according to the selected type is displayed (see
Figure 26. Smart phone and NDEF discover display
UM2949 - Rev 1 page 24/60
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Figure 27. Smart phone and URL NDEF write menu display
UM2949
Main menu
Reading and writing NDEF with the ST25PC-NFC software
To access the NDEF editor screen, start by right-clicking on a ST25DV-I2C tag tag in the "Inventory Pane" (see
), then select the "NDEF Editor" option in the menu. The NDEF interface is illustrated in
The first list on the left of the NDEF Editor screen displays the content of the tag. Click on the "Read from selected tag" button to refresh the list content.
The right-most list helps the user compose an NDEF message. The current tag content is then copied by clicking on the "Edit" arrow located between the two lists. Add a new record by clicking on the "Add new record" button at the bottom right side of the screen. To remove a record from the composition list, click on the "X" icon.
To write the NDEF message to the tag, click on the "Write" icon located between the two lists.
page 25/60
Figure 28. ST25PC-NFC software NDEF interface
UM2949
Main menu
4.2.8
Note:
Clearing the EEPROM
This menu allows the user to clear the EEPROM content. The three choices are:
1.
Write an empty NDEF
2.
Erase the CC file (replace the first four bytes of memory with 0xFF)
3.
Clear EEPROM (fill the whole memory with 0xFF).
Fast transfer mode demonstration menu
This demonstration is intended to show how the ST25DV-I2C tag improves the data exchange between the reader and the MCU using a proprietary protocol based on the ISO15693 standard as opposed to exchanging data through the EEPROM. To perform the data exchange the ST25DV-I2C tag shares a 256-byte RAM buffer available for the reader and the MCU (also called mailbox).
Data exchange is only carried out in one direction at a time (half duplex). The mailbox contains indicators giving the reader status and generates pulses on a GPO, which must be connected to an external interrupt (GPIO input) of the microcontroller. For more details on the mailbox feature, refer to the ST25DV-I2C tag datasheet.
this time, the firmware is initialized, enabling the mailbox functionality and erasing the Flash memory on the
MCU (to store data downloaded through NFC, dedicated demonstration Flash memory area). Then, when the demonstration has finished its initialization, the message "Ready to start demo ! !" is displayed, as shown in
When the Mailbox feature is enabled, the EEPROM is in read only mode. To modify the EEPROM disable the
"Mailbox" feature.
UM2949 - Rev 1 page 26/60
UM2949 - Rev 1
Figure 29. ST25DV64KC-DISCO Fast transfer mode display
UM2949
Main menu
The picture and note icons in
Figure 29 , on the bottom left of the screen, point to a sub-menu that allows the user
to choose a picture or a random data buffer, which is to be transferred to a reader (see
and Host to Reader data transfer sections).
The home icon (bottom right) allows the user to go back to the main menu (see
).
At this step, the firmware is waiting for an action from the reader or from the user to start. These actions are described in the following sections.
Smart phone and Fast transfer mode use cases
•
•
•
•
•
Available actions can be accessed after tag has been taped, and are available in the ST25DV-I2C tag features or demonstrations menus within the application "Drawer".
The available use cases are:
Mailbox management, enable/disable the mailbox and display mailbox register fields status
Data transfer, to demonstrate basics transfers
Firmware upgrade, to demonstrate the firmware upgrade use case
Picture transfer, to demonstrate how to upload or download pictures
Stopwatch synchronization, to demonstrate fast transfer with a smart phone.
The display is illustrated in
page 27/60
Figure 30. Smart phone and Fast transfer mode use cases display
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Main menu
UM2949 - Rev 1
PC software and Fast transfer mode use cases
As with Android ™ phones, all the Fast transfer mode demonstrations are played using the ST25PC-NFC software.
The CR95HF is used as a RF reader, for more information refer to Software toolbox for NFC tags user manual
(UM2444), available on www.st.com
.
To access the Fast transfer mode screen, start by right-clicking on a ST25DV-I2C tag tag in the "Inventory" pane (see
Figure 31 ), then select the "Fast Transfer Mode" option in the menu. Two tabs appear below the
tag selection box "Read Message" (by default) and "Write Message". Click on the "Write Message" tab (see
The message area allows the user to write up to 256 bytes of data. A "Fill with" button fills up the whole buffer with the specified byte value. After the message is written it is sent to the tag mailbox by clicking on the "Write
Message" button.
Click on "Read Register" to the right of the screen to read the values of the tag dynamic registers.
page 28/60
Figure 31. ST25PC-NFC software - ST25DV-I2C tag FTM interface Write tab
UM2949
Main menu
Once the tag mailbox is filled , switch to the "Read message" tab (see Figure 32
).
Figure 32. ST25PC-NFC software - ST25DV-I2C tag FTM interface Read tab
UM2949 - Rev 1
Click on the "Read Message Length" button to get the size in bytes of the mailbox content, and on the "Read
Message" button to display the current content of the mailbox.
illustrates how to access them.
Available demonstrations are:
• "Reader-to-Host" and "Host-to-Reader" R2H data transfer: transfer of binary file to/from PC software (using the CR95HF board) to and from the ST25DV64KC-DISCO board.
page 29/60
UM2949 - Rev 1
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Main menu
•
•
Reader-to-Host" firmware upgrade: transfer of binary file containing a new STM32 firmware from PC software (using CR95HF board) to ST25DV64KC-DISCO board, the ST25DV64KC-DISCO firmware is upgraded.
"Reader-to-Host" and "Host-to-Reader" image transfer: transfer of JPG image to/from PC software (using
CR95HF board) to and from the ST25DV64KC-DISCO board, the image is displayed on ST25DV64KC-
DISCO LCD.
Figure 33. ST25PC-NFC software - Access to ST25V-I2C FTM demonstrations
Smart phone and FTM data transfers
Several menus accessible by the drawer menu are dealing with the Fast transfer mode data transfers:
•
•
•
Mailbox management. Radio buttons give the current status of the mailbox, and this menu permits to enable/ disable the mailbox feature
FTM demonstrations:
– Send or receive data
– Firmware update
– Send or receive pictures.
Stopwatch transfers: This demonstration shows a chronometer synchronized between the smart phone and the tag using the mailbox. It shows the low latency.
page 30/60
UM2949
Main menu
Figure 34. ST25DV drawer menu (Mailbox management, FTM demonstration, Stopwatch demonstration)
UM2949 - Rev 1
As prerequisite to any data transfer, the mailbox has to be enabled, without any pending message. The correct
.
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Figure 35. Mailbox status
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Main menu
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Figure 36. Data transfers from reader to tag of a random buffer
UM2949
Main menu
Note:
Note:
According to data size selected, the corresponding payload data is initialized with random values on which a
CRC is computed to be sure that the host computes the same data after each transfer.
For every transfers done with the Android™ application, the user can choose between two modes:
•
•
Error recovery enabled. With this mode, the protocol is able to detect transmission errors and to recover
(by retransmitting the faulty packets). This is the default (and recommended) mode.
Error recovery disabled. Data transfer is done at max throughput. There is no recovery in case of transmission error.
PC software and FTM data transfers
In the ST25DV-I2C tag/ST25DV-DISCOVERY "Demos" menu (see
Figure 33 ), select the "FTM – Data Transfer"
item which leads to the "Data. Transfer Demo" in Figure 37
.
To execute a R2H data transfer, select the "Send a file" item from the command list. A window pops-up asking the user to select a file to transfer to the ST25DV64KC-DISCO board. CRC computation is done when loading the file.
Then click on the "Start" button to start transferring data to the board.
UM2949 - Rev 1 page 33/60
Figure 37. Software R2H data transfer display
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Main menu
UM2949 - Rev 1
A progress bar and a timer display the transfer progress.
At the end of the transfer, the CRC calculated by the ST25DV64KC-DISCO board is compared with the CRC calculated by the PC software. Demonstration duration is displayed too.
Reader to host firmware upgrade
This function allows the user to send data (that is manipulated as binary) from the reader to the STM32L476xx microcontroller device. The data is stored in the Flash memory and at the end of the transfer, the following instruction code jumps to the new firmware location, demonstrating the capability to transfer large mounts of binary data. For this example, the new firmware is stored in a secondary area in the Flash memory and it is not intended to be used for new demonstrations. To come back to the initial firmware, press the reset button and it reboots the reader with the with this firmware.
To prepare the ST25DV64KC-DISCO for the firmware upgrade demonstration, power up the board, then touch the
FTM icon to start the fast transfer mode demonstration (
The kit is now waiting for a reader action (see Smart phone and firmware upgrade and
ST25DV-
DISCOVERY\Demonstrations\ST25DVDemo_FwUpgd\Binary folder
To execute the firmware download, the user first has to send (from the reader) a correct password (for this demonstration the password is 0x12345678). During the password check, the Flash memory area where the firmware is to be stored is erased (
page 34/60
Figure 38. ST25DV64KC-DISCO firmware upgrade: password check
UM2949
Main menu
If the password is correct, the user is authorized to start the transfer (
Figure 39 ), if not, the user has to enter a new password to continue ( Figure 40
).
Figure 39. ST25DV64KC-DISCO firmware upgrade: password OK
Figure 40. ST25DV64KC-DISCO firmware upgrade: wrong password
UM2949 - Rev 1
During the transfer the full length of data transmitted is displayed, and a bar indicates the progress (see
page 35/60
Figure 41. Software end transfer status display
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Main menu
When the transfer is successfully completed, the computed CRC and the transfer time are displayed (see
Figure 42 ). In case of failure the display shows an error message.
Figure 42. ST25DV64KC-DISCO firmware upgrade: transfer done
UM2949 - Rev 1
To start the new firmware, simply tap the screen.
Smart phone and firmware upgrade
Features:
• Upgrade a new firmware to the ST25DV64KC-DISCO board.
Demonstration steps, see the screen illustration in Figure 43
:
1.
Check the mailbox status (Must be enable, withtout any pending messages in the mailbox).
2.
Select the “Firmware demos” in the drawer menu and click on “Firmware update button”.
3.
Select the file to be downloaded.
4.
A pop up asks for a password. By default, and for demonstration purpose the password is 12345678.
5.
Start download = Start transfer button.
6.
Smart phone and firmware download.
page 36/60
UM2949 - Rev 1
Figure 43. Smart phone and firmware upgrade display
UM2949
Main menu
PC software and firmware upgrade
In the ST25DV-I2C tag/ST25DV-DISCOVERY "Demos" menu (see
Figure 33 ), select the "FTM – Firmware
Upgrade" item.
To execute a R2H firmware upgrade, first select a binary file to send with the "Select File" button (see
CRC computation is done when loading the file, and is displayed on the screen.
To start the firmware upgrade, click on the "Send to RF" button. Status of the transfer is updated in real time illustrated by the "Transfer rate" progress bar.
page 37/60
Figure 44. PC software R2H successful firmware upgrade
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Main menu
UM2949 - Rev 1
Reader to host image download
This function sends data from the reader to the STM32L476xx microcontroller device. In this demonstration, data is composed of jpeg images, stored in the Flash memory and displayed when the transfer is successful.
To prepare the ST25DV64KC-DISCO for the R2H picture transfer demonstration, power on the board, then touch the FTM icon to start the fast transfer mode demonstration (see
It is now waiting for a reader action to continue the demonstration, as illustrated in the
Smart phone and picture transfers
and Smart phone and picture download transfer
sections.
During the transfer, the full length of data transmitted is displayed and a progress bar indicates the progression.
When the transfer is successfully done, the computed CRC and transfer duration are displayed on screen. To display the downloaded picture touch the screen. To return to the Fast transfer mode demonstration simply touch the screen.
Smart phone and picture transfers
Features:
•
•
Send a picture to the tag.
Receive a picture from the tag.
Picture upload steps:
1.
Check the mailbox status (c.f. drawer menus).
2.
Select “FTM demos” in drawer menu.
page 38/60
3.
Click on “Send picture to tag” Select a picture in phone memory.
The upload display screens are illustrated in
Figure 45. Transfer from smart phone to tag
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Main menu
UM2949 - Rev 1 page 39/60
Figure 46. Image transfer demonstration: send a picture
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Main menu
UM2949 - Rev 1
PC software and image transfer
In the ST25DV-I2C tag/ST25DV-DISCOVERY "Demos" menu (see
"FTM – Picture Transfer" item.
To run a R2H transfer (from CR95HF reader to Host board), first select the "Pick a picture to upload" item from the
). Choose a file from the window that pops up, then click on the "Start" button.
page 40/60
Figure 47. PC software R2H image transfer display
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Main menu
UM2949 - Rev 1
Host to reader image upload
This function sends data from the STM32L476xx microcontroller device to the reader (H2R).
In this demonstration, the data is composed of jpeg images, it is written to the mailbox each time it is free, and the
GPO returns the information to the MCU when the reader reads the mailbox message.
To start this demonstration the user must perform an action on the firmware side.
The picture icon at bottom left allows the user to enter a new menu (see Figure 48
), which lets the user choose the pictures to send to the reader. By touching the screen on the left or right border the user scrolls between the different pictures available for transfer, simply touch the image on screen to select it. To come back and cancel the action, touch the arrow at the bottom of the screen.
page 41/60
UM2949 - Rev 1
Figure 48. ST25DV64KC-DISCO select picture to upload
UM2949
Main menu
After selecting the picture to transfer, the firmware writes the first chunk in the mailbox and waits for the message to be read. During the transfer, a file size and a progress bar are displayed, as shown in
Figure 49. ST25DV64KC-DISCO image upload start
The kit is now waiting for the reader to read the message in the mailbox (see
Smart phone and picture transfers
and PC software and picture upload transfer sections) to continue the demonstration.
When the transfer is successfully completed, the computed CRC and transfer time are displayed on the screen
). In case of failure, the display shows an error message.
Figure 50. ST25DV64KC-DISCO image upload successful page 42/60
To return to the Fast transfer mode demonstration simply touch the screen.
Smart phone and picture download transfer
Features: same as Smart phone and picture transfers
.
Picture download steps:
1.
Check MB registers
2.
Select “FTM demos” in the drawer menu
3.
Received picture from tag button. Select a picture on the ST25 discovery kit. The transfer starts.
Smart phone and picture upload transfers display
Figure 51. Smart phone and picture upload transfers display
UM2949
Main menu
UM2949 - Rev 1
PC software and picture upload transfer
In the ST25DV-I2C tag/ST25DV-DISCOVERY "Demos" menu (see
Figure 33 ), select the "FTM – Picture Transfer"
item. The H2R image transfer display is illustrated in
Figure 52. PC software H2R image transfer display
.
page 43/60
UM2949
Main menu
To initiate the transfer, choose a picture from the ST25DV64KC-DISCO board. Then click on the "Start" button to start the transfer from the board to the reader. CRC computation is done when all data is transferred, then it is sent to the tag.
The demonstration ends when the PC software receives the acknowledgment and displays the image .
Figure 52. PC software H2R image transfer display
UM2949 - Rev 1
Host to Reader data transfer
This function allows the user to send data from the STM32L476xx microcontroller device to the reader. In this demonstration, the data takes random binary values. Each time the mailbox is free the MCU writes data, and the
GPO informs it when the reader consumes the mailbox message.
To start this demonstration the user needs to perform an action on firmware side. The data icon at bottom left allows the user to enter a new menu; the size of the data transfer (from the MCU to a reader) is selected from 1 to
999 kB, using the keyboard shown in Figure 53
. The inputs are corrected by using the arrow on the bottom left. To cancel and return to the Fast transfer mode menu touch the arrow at the bottom of the screen. After entering the correct size, touch the "Ok" icon.
page 44/60
UM2949 - Rev 1
Figure 53. ST25DV64KC-DISCO select H2R data size to transfer display
UM2949
Main menu
The kit is now waiting for a reader to read the message on the mailbox (see
Smart phone and H2R data transfer
section) to continue the demonstration.
).
In case of failure, the display shows an error message.
To return to the Fast transfer mode demonstration simply touch the screen.
Smart phone and H2R data transfer
To start the demonstration after prerequisites setting checked, go to “FTM demos” menu.
After having selected the buffer size to send from ST25DV64KC-DISCO board, user can click on “Receive data from tag” button to start the transfer.
page 45/60
Figure 54. Smart phone and data transfers H2R with selected size
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Main menu
UM2949 - Rev 1
PC software and H2R data transfer
In the ST25DV-I2C tag/ST25DV-DISCOVERY "Demos" menu (see
Figure 33 ), select the "FTM – Picture Transfer"
item.
To send data from the ST25DV64KC-DISCO board to the HF reader, select "Receive a buffer in a file" in the command menu.
Select the buffer size to be sent from the ST25DV64KC-DISCO board and click on the "Start" button to start the transfer of data from the board. CRC computation is done when all data is transferred, then it is sent to the tag.
page 46/60
Figure 55. PC software H2R data transfer display
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Main menu
UM2949 - Rev 1
The demonstration ends when the PC software receives acknowledgment and saves the data in a file. A window pops up at the end of the transfer to select the file location.
Stopwatch demonstration
This demonstration shows how fast a smart phone updates the mailbox.
The smart phone sends, as fast as possible, stopwatch values (8-byte frames) to the MCU using the mailbox. The
MCU displays these values on the LCD screen and computes the duration between two consecutive updates. The average and maximum inter-frame durations are refreshed and displayed after the reception of 20 frames.
To run the demonstration
1.
On the ST25DV64KC-DISCO board, enter the Fast transfer mode menu.
2.
On the smart phone: open the ST25 NFC App, tap the ST25DV-I2C tag and go to the "Stopwatch Transfers" menu and click on Start button.
page 47/60
UM2949 - Rev 1
Figure 56. ST25DV64KC-DISCO stopwatch start
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Main menu
Smart phone and stopwatch transfers
In this demonstration the smart phone sends, as fast as possible, stopwatch values (8-byte frames) to the MCU using the mailbox. The main features are
• Configuration of the “Mail Box” register [Enable / Disable MB, Watchdog)
•
•
•
– Selection of static or dynamic registers
– Read Cfg to retrieve MB status
Start: Starts the stopwatch, the display is updated accordingly, and frames are sent to the host if a tag is in the field. The display is updated, starting from 00:00:00 (minutes:seconds:milliseconds)
Stop: Stops the stopwatch. When restarted, the stopwatch restarts from 00:00:00.
Pause: Pauses the stopwatch
• Resume: resumes the stopwatch after a pause
On the smart phone open the ST25 NFC application, tap the ST25DV and go to the “Stopwatch Transfers” menu and click on Start button. Pause and Resume buttons can then be used.
page 48/60
Figure 57. Smart phone and stopwatch transfers
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Main menu
UM2949 - Rev 1
PC software and stopwatch demonstration
In the ST25DV-I2C tag/ST25DV-DISCOVERY "Demos" menu (see
Figure 33 ), select the "FTM – Picture Transfer"
item.
Click on the "Start" button to begin sending time data to the board.
Click on "Pause" to temporarily stop the timer. The "Resume" button starts the timer where it left off.
Click on "Stop" to definitely stop the timer.
page 49/60
Figure 58. ST25PC-NFC software and Stopwatch demonstration
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Main menu
UM2949 - Rev 1 page 50/60
A.1
A.2
UM2949
FTM protocol details
Appendix A FTM protocol details
Introduction
The new FTM protocol has been introduced to bring the following benefits:
•
•
•
•
Protocol is integrated into the ST25SDK so that every application, whether on Android ™ , iOS ™ , or PC, can use it. The previous protocol was fully managed by the applications.
Simplify the use of the Fast transfer mode: a single API function takes care of the transmission, whatever the data size. The users do not need to split the data and neither do they need to acknowledge it anymore.
Short overhead in order to optimize the data rate.
Robust in case of errors or if the tag is moved out and back in the RF field. The transmission is be able to restart and to complete without error.
The NFC reader (for example a smart phone) is always the initiator of all communications.
The new protocol is available on MB1286 “ST25DV-Discovery board” and on MB1396 “ST25DV64KC-DISCO board”.
Operating modes
The protocol is able to operate in two modes:
•
•
A mode with error recovery: This mode is robust in case of transmission error or packet lost.
A mode without error recovery. This mode gives the priority to the transfer speed but is not able to recover in case of error.
For both modes, the data to transfer must be split to fit in the ST25DV-I2C Mailbox (which can contain up to 256 bytes). «Packet» is called the amount of data that fits into the ST25DV mailbox.
Depending of the size of the data to send, there are one or more «packets» to transmit.
When sending big data files (like images or firmware data), it is interesting to detect transmission errors early and to be able to resent only the failing packets. The user could use a CRC for the whole file but in case of error, the user has to resend the whole file. The user could use a CRC to acknowledge each packet but this has a big impact on performance. Instead a CRC can be used to acknowledge a group of packets. This group of packets is called a “segment”.
A CRC is computed on all the data of the segment. If the CRC is correct, all the packets of the segment are considered as valid. Otherwise, an error is sent to the transmitter and all the packets of the current segment have to be resent.
Depending of the use case, the application has the possibility to change the number of packets per segment. In the ST25SDK, the default setting is 20 packets per segment (= 4900 Bytes per segment).
Example of transmission with three packets per segment:
Figure 59. Example of transmission with three packets per segment
Packet1 Packet2 Packet3 Packet4 Packet5 Packet6 Packet7
Segment1
(a CRC is computed for those 3 packets)
Segment2
(a CRC is computed for those 3 packets)
Segment3
(containing a single packet it also contains CRC)
Data to send
MS54572V1
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A.3
UM2949
Low-level protocol
Low-level protocol
A low-level protocol has been defined to:
•
•
•
Split the data to be sent into packets (a small header is added to indicate the content of the packet)
Ensure their transmission
Possibly: check the validity of the data received and acknowledge it
This protocol allows user to send data of any size, both ways.
Each packet starts with a “Control Byte” or a “Status Byte”:
1.
A “Control Byte” is used to indicate the bytes present in the packet (packet data length, total, data length,
CRC presence and so on).
Figure 60. Structure of a packet
C L TL DATA CRC Unused Bytes
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Packet
Max mailbox size: 256 Byte
MS54573V1
2.
A “Status Byte” is a single Byte sent in response to one or more received packets to indicate if the transmission was successful or not.
Figure 61. Structure of a status packet
S
Status Byte
(1 byte)
Unused Bytes
MS54574V1
The following table describes the content structure of the control byte.
Table 3. Control byte structure definition
Bit number
Bit 7
Bit 6
Bit 5
Bit 4
Description
This bit must be set to 0 for a control byte (it is used to distinguish control bytes and status bytes).
Bit indicating if a packet data length field (on one byte) is present. It indicates the length of the data present in this packet (including the CRC bytes, if any). If no packet data length field is present, the receiver considers that the packet has the max possible size.
Segment End. When this bit is set, a CRC is present in this packet. The CRC is calculated on all the data present between “Segment Start” and “Segment End”. An acknowledge must be sent by the receiver.
Segment Start page 52/60
A.4
UM2949
ST Light Protocol
Bit number
Bit 3 - 2
Bit 1
Bit 0
•
Description
–
–
Bits used to indicate data split on several packets. They have the following meaning:
– b00: Data fitting in a single packet.
– b01: First packet of a serie of packets. In that case, a total length field (on 4 bytes) is present. It indicates the length of the data that has been split on several packets.
b10: Middle packet (there can be more than one).
b11: End packet finishing the transfer of the data.
Parity bit toggling for every new segment. It allows to detect the re-transmission of the same segment
Bit indicating if the packet belongs to a segment
The following table describes the content structure of the status byte.
Bit number
Bit 7
Bit 6 - 4
Bit 3 - 0
Table 4. Status byte structure
Description
This bit must be set to 1 for a status byte (to avoid confusion with control bytes)
Reserved
•
•
Status of the last packet(s) received:
00: SEGMENT_OK
01: SEGMENT_ERROR (Ex: CRC error, packet lost…etc)
So a status byte with the value 0x80 corresponds to SEGMENT_OK and 0x81 corresponds to
SEGMENT_ERROR.
ST Light Protocol
On top of previous low level protocol, a light protocol is used to indicate the content of the sent data. This light protocol is used to send commands that can be understood by the receiver.
It is not mandatory to use this light protocol. Users can use their own protocol if they prefer.
In this protocol, the data sent are called “Commands”.
A command starts with a byte called “cmdId” and can be followed by some data:
Figure 62. Structure of a command
0
Cmd
Id
DATA
Command
Byte
MS54575V1
Warning: The most significant bit of the command_id must be set to 0.
Response format:
• The response must start with a response byte that is (0x80 | cmdId). It allows the user to check that the response really matches the command sent. The most significant bit is set to 1 to indicate that it is a response and not a command.
UM2949 - Rev 1 page 53/60
Note:
•
•
Then there is a command status:
– CMD_OK (=0x81) in case of success
– CMD_ERROR (=0x82) in case of error
– CMD_INTERNAL_ERROR (=0x83) in case of internal error (not due to the protocol).
– CMD_UNKNOWN (= 0x84)
– CMD_NOT_ALLOWED (= 0x85): Command not allowed
Then there might be some “Response data”
Figure 63. Structure of a command response
1 Cmd Id
Cmd status
Response data
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ST Light Protocol
Response
Byte
MS54576V1
Beware of the possible confusion between "status bytes" used for acknowledging (SEGMENT_OK = 0x80,
SEGMENT_ERROR = 0x81) and Command Status (CMD_OK = 0x81, CMD_ERROR = 0x82).
The following commands are currently used:
Cmd Id Command name
0x00 FTM_GET_BOARD_INFO
0x01 FTM_SEND_PICTURE
0x02 FTM_READ_PICTURE
0x03 FTM_STOPWATCH
0x04 FTM_FW_UPGRADE
0x05 FTM_SEND_DATA
0x06 FTM_READ_DATA
0x07 FTM_SEND_PASSWORD
0x0F
ECHO
(used only for debug)
Table 5. FTM commands list
Null
Data
Data must contain 2 bytes (0x00, 0x00)
Data must contain the picture
Response data
The response data contains 4 bytes: one indicating the board name and 3 indicating the firmware version
Null
The response data contains the picture read
Data must contain the stopwatch data Null
Data must contain the firmware to send Null
Data must contain the data to send
Null
Null
The response data contains the data read
Data must contain the password to send to grant the Firmware upgrade
The first byte indicates if the STM32 must send a response with or without error recovery (0x00 = without error recovery, 0x01 = with error recovery).
The other bytes can be chosen by the issuer
Null
The response data contains the same bytes has in the command data
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Revision history
Date
03-Fev-22
Table 6. Document revision history
Revision
1 Initial release.
Description of changes
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Contents
Contents
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List of tables
List of tables
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List of figures
List of figures
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List of figures
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