Flash program memory
ST72324B-Auto
24/198
Doc ID13466 Rev 4
Figure 6.
Typical ICC interface
1.
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.
2.
During the ICC 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>1K or a reset management IC with open
drain output and pull-up resistor >1K, 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 OSC1 (OSCIN) 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 OSC2 grounded in this case.
Caution:
External clock ICC entry mode is mandatory in ST72F324B 8/16 Kbyte Flash devices. In
this case pin 9 must be connected to the OSC1 (OSCIN) pin of the ST7 and OSC2 must be
grounded. 32 Kbyte Flash devices may use external clock or application clock ICC entry
mode.
4.5
ICP (in-circuit programming)
To perform ICP the microcontroller must be switched to ICC (in-circuit communication) mode
by an external controller or programming tool.
Depending on the ICP code downloaded in RAM, Flash memory programming can be fully
customized (number of bytes to program, program locations, or selection serial
communication interface for downloading).
When using an STMicroelectronics or third-party programming tool that supports ICP and
the specific microcontroller device, the user needs only to implement the ICP hardware
interface on the application board (see
Figure 6). For more details on the pin locations, refer
to the device pinout description.
ICC connector
ICCDA
T
A
ICCCLK
R
E
SET
V
DD
HE10 connector type
Application
power supply
1
2
4
6
8
10
97
5
3
Programming tool
ICC connector
Application board
ICC cable
(See note 3)
10k
V
SS
ICCSE
L
/VPP
ST7
OSC1
OSC2
Mandatory for
See note 1
See note 2
Application
reset source
Application
I/O
(see note 4)
8/16 Kbyte Flash devices