AS5040 8-bit Programmable Magnetic Rotary Encoder
AS5050 / AS5055
Programmable Magnetic Rotary Encoder
1 VDD General Description
The AS5050/AS5055 is is a single-chip magnetic rotary encoder IC with low voltage and low power features.
It includes 4 integrated Hall elements, a high resolution ADC and a smart power management controller.
The angle position, alarm bits and magnetic field information are transmitted over a standard 3-wire or 4-wire SPI interface to the host processor.
AS5050-AB-v1.1
Adapterboard
OPERATION MANUAL
The absolute angle measurement provides instant indication of the magnet’s angular position with a resolution of:
- AS5050: 0.35° = 1024 positions per revolution
- AS5055: 0.09° = 4096 positions per revolution
The AS5055 is available in a small QFN 16-pin 4x4x0.85mm package and specified over an operating temperature of -20 to +85°C.
2 The AS5050/AS5055 Adapter board
2.1 Board description
The AS5050/AS5055 adapter board is a simple circuit allowing test and evaluation of the AS5050/AS5055 rotary encoder quickly without building a test fixture or PCB.
The PCB can be attached to a microcontroller or to the AS5050/AS5055-DB Demoboard as external device.
J1 connector
Power supply
SPI
3 wire – 4 wire
SPI communication selection
AS5050/AS5055 encoder
INT/ output EN input
4 x 2.6mm mounting holes
Figure 1: AS5050 Adapterboard
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AS5050 / AS5055 Magnetic Rotary Encoder
Adapterboard Operation Manual
2.2 Mounting the AS5050 adapter board
Rotating shaft and magnet holder
Not ferromagnetic (plastic, brass, copper, stainless steel, aluminum…)
Bearing
Casing
Spacer
M2~M2.5 Screw + nut
AS5050-AB PCB
Figure 2: AS5050 adapter board mounting and dimension
A diametric magnet must be placed over on under the AS5050/AS5055 encoder, and should be centered on the middle of the package with a tolerance of 0.5mm.
The airgap between the magnet and the encoder casing should be maintained in the range 0.5mm~2mm.
The magnet holder must not be ferromagnetic. Materials as brass, copper, aluminum, stainless steel are the best choices to make this part.
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AS5050 / AS5055 Magnetic Rotary Encoder
Adapterboard Operation Manual
3 AS5050/AS5055 and adapter board pinout
Int-EN/ 3W – 4W
AS505x
Figure 3: AS5050/AS5055 adapter board connectors and encoder pinout
J1 - 1
J1 - 2
J1 - 3
J1 - 4
J1 - 5
J1 - 6
Pin#
Board
J1 - 7
Pin#
AS5050/
AS5055
7
9
10
11
15
16
8
Symbol
Board
VDDp
VDD
GND
INT/
MOSI
MISO
S C K
Type Description
S
S
S
DIO
DI
DO
Peripheral power supply, 1.8V ~ VDD
Analog and digital power supply, 3.0 ~ 3.6V
Supply ground
Interrupt output. Active LOW, when conversion is finished
SPI bus data input
SPI bus data output
DI_PD SPI Clock Schmitt trigger
J1 - 8
JP1
JP2
8
7
1
S
S
/
/
Wire_Mode
INT_EN/
DI_PD SPI Slave Select, active LOW
S
DO_OD
3 wire mode or 4 wire mode SPI communication
Close: enable INT/ output
Pin 1 is the AS505x En_INT/ input. Can be used for interrupt daisy chain (see chapter 4.3)
Table 1: Pin description
Pin types: DO_OD digital output open drain
DO digital output
DI_PD digital input pull-down
DI_PU digital input pull-up
S
DI
DO_T
ST supply pin digital input digital output / tri-state
Schmitt-Trigger input
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AS5050 / AS5055 Magnetic Rotary Encoder
Adapterboard Operation Manual
4 Operation use cases
4.1 One device SPI mode, unidirectional – 3 wire
The AS5050-AB can be directly connected to an industry standard SPI port of a microcontroller. The minimum connection requirement for unidirectional communication
(angle + alarm values reading) between the microcontroller and the AS5050/AS5055 are MISO, SCK,
SS/.
The angle will be read at each 16-bit SPI transfer. See
AS5050/AS5055 datasheet register table, register
3FFFh.
This value must be read with a period of 600µs or more in order to get a new angle position.
The INT/ signal can be attached o the microcontroller to indicate that a new angle position has been calculated.
4.2 One device SPI mode, bidirectional – 4 wire
If other registers than only angle value have to be read, or in order to write registers into the AS5050/AS5055, the signal MOSI is necessary.
The INT/ signal can be attached o the microcontroller to indicate that a new angle position has been calculated.
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AS5050 / AS5055 Magnetic Rotary Encoder
Adapterboard Operation Manual
4.3 Multi devices SPI Daisy chain mode
The AS5050/AS5055 can be daisy chained, using 4 wires only for SPI communication.
In this configuration with n x encoders, the sequence will be processed as follow:
- MCU sets SS/ = 0
- MCU shifts n x 16-bit (e.g. READ command FFFFh) through the chain
- MCU sets SS/=1
At that point all the n x encoders have received the
READ command FFFFh.
- MCU sets SS/=0
- MCU shifts n x 16-bit (e.g. NOP command 0000h)
- MCU sets SS/=1
At that point the n x 16-bit received on MISO are the n x angle values.
If an interrupt is needed, the signal INT/ can be daisy chained as shown on the diagram on the left. The final
INT/ signal connected to the MCU will go LOW only if all the n x encoders INT/ = 0. The n x 16-bit angle readout can be performed here.
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AS5050 / AS5055 Magnetic Rotary Encoder
Adapterboard Operation Manual
5 Firmware coding
The following source code fits the 4-Wire application (chapter 4.2).
The function
void
spiReadData() reads/writes 3 values from the AS5050/AS5055
- Send command READ AGC / Receive value unknown
- Send command READ Angle / Receive value AGC
- Send command NOP (no operation) / Receive value ANGLE
If a READ ANGLE only is necessary in a loop, the procedure can be reduced to one line:
- Send command READ Angle / Receive value Angle (T-1)
The function
static u8 spiCalcEvenParity(ushort value)
is optional, it calculates the parity bit of the 16-bit SPI stream.
/*!
*****************************************************************************
* Reads out chip data via SPI interface
*
* This function is used to read out cordic value from chips supporting SPI
* interface.
*****************************************************************************
*/
#define SPI_CMD_READ 0x8000 /*!< flag indicating read attempt when using SPI interface */
#define SPI_REG_DATA 0x7ffe /*!< data register when using SPI */
#define SPI_REG_AGC 0x7ff0 /*!< agc register when using SPI */
#define SPI_REG_CLRERR 0x6700 /*!< clear error register when using SPI */
void spiReadData()
{
u16 dat;
ushort angle, agcreg;
ubyte agc;
ushort value;
bit alarmHi, alarmLo;
// 16-bit data buffer for SPI communication
/* Send READ AGC command. Received data is thrown away: this data comes from the precedent command (unknown)*/
dat = SPI_CMD_READ | SPI_REG_AGC;
dat |= spiCalcEvenParity(dat);
spiTransfer((u8*)&dat, sizeof (u16));
/* Send READ ANGLE command. Received data is the AGC value, from the precedent command */
dat = SPI_CMD_READ | SPI_REG_DATA;
dat |= spiCalcEvenParity(dat);
spiTransfer((u8*)&dat, sizeof (u16));
agcreg = dat;
/* Send NOP command. Received data is the ANGLE value, from the precedent command */
dat = 0x0000; // NOP command.
spiTransfer((u8*)&dat, sizeof (u16));
angle = dat >> 2;
} if (((dat >> 1) & 0x1) || ((agcreg >> 1) & 0x1))
{
/* error flag set - need to reset it */
dat = SPI_CMD_READ | SPI_REG_CLRERR;
dat |= spiCalcEvenParity(dat);
spiTransfer((u8*)&dat, sizeof (u16));
} else
{
agc = (agcreg >> 2) & 0x3f;
value = (dat >> 2) & 0x3fff;
angle = (value * 360) / 4095;
alarmLo = (dat >> 14) & 0x1;
alarmHi = (dat >> 15) & 0x1;
// AGC value (0..63)
// Angle value (0..4095 for AS5055)
// Angle value in degree (0..359.9°)
}
}
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AS5050 / AS5055 Magnetic Rotary Encoder
Adapterboard Operation Manual
/*!
*****************************************************************************
* Calculate even parity of a 16 bit unsigned integer
*
* This function is used by the SPI interface to calculate the even parity
* of the data which will be sent via SPI to the encoder.
*
* \param[in] value : 16 bit unsigned integer whose parity shall be calculated
*
* \return : Even parity
*
*****************************************************************************
*/
static u8 spiCalcEvenParity(ushort value)
{
u8 cnt = 0;
u8 i; for (i = 0; i < 16; i++)
{ if (value & 0x1)
{
cnt++;
}
value >>= 1;
} return cnt & 0x1;
}
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AS5050 / AS5055 Magnetic Rotary Encoder
Adapterboard Operation Manual
6 AS5050 adapter board hardware
6.1 AS5050-AB-1.1 schematics
JP1: SPI wire mode:
1-2: 4 wires SPI
2-3: 3 wires SPI
MOSI
MISO
SCK
SS/
GND
Int_INT/
1
2
3
4
17
VDDp
1
JP1
Jumper3
MOSI
MISO
SCK
SS/
Plane
GND
3
U1
VDD
VDDp
INT_en/
Test
AS5055
GND
12
11
10
9
GND
GND
VDD
VDDp
SS/
SCK
MISO
MOSI
Int_INT/
J1
8
7
6
5
4
3
2
1
Header 8
VDDp
1
VDD
R1
15R
C1
4.7u
C2
100n
GND
JP2
2
GND
Jumper2
JP2: Extern INT/ enable
- Closed: Interrupt output enabled (default)
- Open: Secondary device INT/ output on pin 1
(daisy chain)
Note:
AS5050-AB-1.1
On AS5050/AS5055-AB version 1.0, U1 pin 16 is connected to VSS, inducing a higher current consumption of the IC. This has been fixed on v1.1 or higher.
AMS
Figure 4: AS5050-AB-1.1 adapterboard schematics
6.2 AS5050-AB-1.1 PCB layout
1.1
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Figure 5: AS5050-AB-1.0 adapter board layout
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AS5050 / AS5055 Magnetic Rotary Encoder
Adapterboard Operation Manual
Table of contents
1 VDD General Description .................................................................................................................................................. 1
2 The AS5050/AS5055 Adapter board ................................................................................................................................. 1
2.1
Board description...................................................................................................................................................... 1
2.2
Mounting the AS5050 adapter board........................................................................................................................ 2
3 AS5050/AS5055 and adapter board pinout....................................................................................................................... 3
4 Operation use cases.......................................................................................................................................................... 4
4.1
One device SPI mode, unidirectional – 3 wire .......................................................................................................... 4
4.2
One device SPI mode, bidirectional – 4 wire ............................................................................................................ 4
4.3
Multi devices SPI Daisy chain mode......................................................................................................................... 5
5 Firmware coding ................................................................................................................................................................ 6
6 AS5050 adapter board hardware ...................................................................................................................................... 8
6.1
AS5050-AB-1.0 schematics...................................................................................................................................... 8
6.2
AS5050-AB-1.0 PCB layout...................................................................................................................................... 8
Table of contents........................................................................................................................................................................ 9
Copyrights ................................................................................................................................................................................ 10
Disclaimer................................................................................................................................................................................. 10
Contact Information .................................................................................................................................................................. 10
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AS5050 / AS5055 Magnetic Rotary Encoder
Adapterboard Operation Manual
Copyrights
Copyright © 1997-2010, austriamicrosystems AG, Schloss Premstaetten, 8141 Unterpremstaetten, Austria-Europe.
Trademarks Registered ®. All rights reserved. The material herein may not be reproduced, adapted, merged, translated, stored, or used without the prior written consent of the copyright owner.
All products and companies mentioned are trademarks or registered trademarks of their respective companies.
Disclaimer
Devices sold by austriamicrosystems AG are covered by the warranty and patent indemnification provisions appearing in its
Term of Sale. austriamicrosystems AG makes no warranty, express, statutory, implied, or by description regarding the information set forth herein or regarding the freedom of the described devices from patent infringement. austriamicrosystems
AG reserves the right to change specifications and prices at any time and without notice. Therefore, prior to designing this product into a system, it is necessary to check with austriamicrosystems AG for current information. This product is intended for use in normal commercial applications. Applications requiring extended temperature range, unusual environmental requirements, or high reliability applications, such as military, medical life-support or lifesustaining equipment are specifically not recommended without additional processing by austriamicrosystems AG for each application.
The information furnished here by austriamicrosystems AG is believed to be correct and accurate. However, austriamicrosystems AG shall not be liable to recipient or any third party for any damages, including but not limited to personal injury, property damage, loss of profits, loss of use, interruption of business or indirect, special, incidental or consequential damages, of any kind, in connection with or arising out of the furnishing, performance or use of the technical data herein. No obligation or liability to recipient or any third party shall arise or flow out of austriamicrosystems AG rendering of technical or other services.
Contact Information
Headquarters
austriamicrosystems AG
A-8141 Schloss Premstaetten, Austria
Tel: +43 (0) 3136 500 0
Fax: +43 (0) 3136 525 01
For Sales Offices, Distributors and Representatives, please visit: http://www.austriamicrosystems.com
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