ST7LITE20F2 View Datasheet(PDF) - STMicroelectronics
Part Name
Description
MFG CO.
ST7LITE20F2
STMicroelectronics
'ST7LITE20F2' PDF : 166 Pages View PDF
ST7LITE20F2 ST7LITE25F2 ST7LITE29F2
Flash program memory
4.3.2
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.
4.4
ICC interface
ICP needs a minimum of 4 and up to 6 pins to be connected to the programming tool. These
pins are:
● RESET: device reset
● VSS: device power supply ground
● ICCCLK: ICC output serial clock pin
● ICCDATA: ICC input serial data pin
● CLKIN/PB4: main clock input for external source
● VDD: application board power supply (optional).
If the ICCCLK or ICCDATA pins are only used as outputs in the application, no signal
isolation is necessary. As soon as the Programming Tool is plugged to the board, even if an
ICC session is not in progress, the ICCCLK and ICCDATA pins are not 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 Programming
Tool documentation for recommended resistor values.
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
5mA 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>1 kΩ or a reset management IC with open drain output and pull-up resistor > 1 kΩ, 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.
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.
Pin 9 has to be connected to the CLKIN/PB4 pin of the ST7 when the clock is not available
in the application or if the selected clock option is not programmed in the option byte. ST7
devices with multi-oscillator capability need to have OSC1 and OSC2 grounded in this case.
With any programming tool, while the ICP option is disabled, the external clock has to be
provided on PB4.
Doc ID 8349 Rev 5
21/166
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