ST7LITEU05 ST7LITEU09
4.3.2
Flash program memory
Depending on the ICP Driver code downloaded in RAM, Flash memory programming can be fully customized (number of bytes to program, program locations, or selection of the serial communication interface for downloading).
In Application Programming (IAP)
This mode uses an IAP driver program previously programmed in sector 0 by the user (in
ICP mode).
This mode is fully controlled by user software. This allows it to be adapted to the user application, (user-defined strategy for entering programming mode, choice of communications protocol used to fetch the data to be stored etc.)
IAP mode can be used to program any memory areas except sector 0, which is write/erase protected to allow recovery in case errors occur during the programming operation.
ICP needs a minimum of 4 and up to 6 pins to be connected to the programming tool. These pins are:
• RESET: device reset
• V
SS
: device power supply ground
• ICCCLK: ICC output serial clock pin (see note 1)
• ICCDATA: ICC input serial data pin
• CLKIN: main clock input for external source
• V
DD
: application board power supply (see note 3)
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Flash program memory
APPLICATION
POWER SUPPLY
(See Note 3)
ST7LITEU05 ST7LITEU09
Figure 6. Typical ICC interface
PROGRAMMING TOOL
ICC CONNECTOR
ICC Cable
ICC CONNECTOR
HE10 CONNECTOR TYPE
OPTIONAL
(See Note 4) 9 7 5
10 8 6 4
3 1
2
APPLICATION BOARD
3.3k
Ω
(See Note 5)
APPLICATION
RESET SOURCE
See Note 2
See Note 1 and Caution
See Note 1
APPLICATION
I/O
ST7
1. If the ICCCLK or ICCDATA pins are only usedas outputs in the application, no signal isolation is necessary.
As soon as the programming tool isplugged to the board, even if an ICC session is not in progress, the
ICCCLK and ICCDATA pins arenot available for the application. If they are used as inputs by the application, isolation such as a serial resistor has to be implemented in case another device forces the signal. Refer to the programmingtool documentation for recommended resistor values.
2. During the ICP session, the programming tool must control the RESET pin. This can lead to conflicts between the programming tool and the application reset circuit if it drives more than 5 mA at high level
(push pull output or pull-up resistor < 1K). A schottky diode can be used to isolate the application RESET circuit in this case. When using a classical RC network with R>1K or a reset management IC with open drain output and pull-up resistor >1 K, no additional components are needed. In all cases the user must ensure that no external reset is generated by the application during the ICC session.
3. The use of Pin 7 of the ICC connector depends on the programming tool architecture. This pin must be connected when using most ST programming tools (it is used to monitor the application power supply).
Please refer to the programming tool manual.
4. Pin 9 has to be connected to the CLKIN pin of the ST7 when ICC mode is selected with option bytes disabled (35-pulse ICC entry mode). When option bytes are enabled (38-pulse ICC entry mode), the internal RC clock is forced, regardless of the selection in the option byte.
5. A serial resistor must be connected to ICC connector pin 6 in order to prevent contention on PA3/RESET pin. Contention may occur if a tool forces a state on RESET pin while PA3 pin forces the opposite state in output mode. The resistor value is defined to limit the current below 2 mA at 5 V. If PA3 is used as output push-pull, then the application must be switched off to allow the tool to take control of the RESET pin
(PA3). To allow the programming tool to drive the RESET pin below V when a pull-up is placed on PA3 for application reasons.
IL
, special care must also be taken
Caution: During normal operation, ICCCLK pin must be pulled- up, internally or externally (external pull-up of 10k mandatory in noisy environment). This is to avoid entering ICC mode unexpectedly during a reset. In the application, even if the pin is configured as output, any reset puts it back in input pull-up.
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