Datasheet

ST7LITE0xY0, ST7LITESxY0
14/124
FLASH PROGRAM MEMORY (Cont’d)
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
–V
SS
: device power supply ground
– ICCCLK: ICC output serial clock pin
– ICCDATA: ICC input serial data pin
– CLKIN: main clock input for external source
–V
DD
: application board power supply (option-
al, see Note 3)
Notes:
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 de-
vice forces the signal. Refer to the Programming
Tool documentation for recommended resistor val-
ues.
2. During the ICP session, the programming tool
must control the RESET
pin. This can lead to con-
flicts between the programming tool and the appli-
cation 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 appli-
cation RESET circuit in this case. When using a
classical RC network with R>1K or a reset man-
agement IC with open drain output and pull-up re-
sistor>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 Program-
ming 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 the clock is not available in the ap-
plication or if the selected clock option is not pro-
grammed in the option byte.
Caution: During normal operation, ICCCLK pin
must be pulled- up, internally or externally (exter-
nal pull-up of 10K mandatory in noisy environ-
ment). This is to avoid entering ICC mode unex-
pectedly during a reset. In the application, even if
the pin is configured as output, any reset will put it
back in input pull-up.
Figure 6. Typical ICC Interface
ICC CONNECTOR
ICCDATA
ICCCLK
RESET
VDD
HE10 CONNECTOR TYPE
APPLICATION
POWER SUPPLY
1
246810
975 3
PROGRAMMING TOOL
ICC CONNECTOR
APPLICATION BOARD
ICC Cable
(See Note 3)
ST7
CLKIN
OPTIONAL
See Note 1
See Note 1 and Caution
See Note 2
APPLICATION
RESET SOURCE
APPLICATION
I/O
(See Note 4)
1