Datasheet

DocID8349 Rev 7 23/170
ST7LITE20F2 ST7LITE25F2 ST7LITE29F2 Flash program memory
169
Caution: During normal operation the 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 will put it back in input pull-up.
Figure 5. Typical ICC interface
4.5 Memory protection
There are two different types of memory protection: Read-Out Protection and Write/Erase
Protection which can be applied individually.
4.5.1 Read-out protection
Read-out protection, when selected provides a protection against program memory content
extraction and against write access to Flash memory. Even if no protection can be
considered as totally unbreakable, the feature provides a very high level of protection for a
general purpose microcontroller. Both program and data E
2
memory are protected.
In flash devices, this protection is removed by reprogramming the option. In this case, both
program and data E
2
memory are automatically erased and the device can be
reprogrammed.
Read-out protection selection depends on the device type:
• In Flash devices it is enabled and removed through the FMP_R bit in the option byte.
• In ROM devices it is enabled by mask option specified in the Option List.
4.5.2 Flash write/erase protection
Write/erase protection, when set, makes it impossible to both overwrite and erase program
memory. It does not apply to E
2
data. Its purpose is to provide advanced security to
applications and prevent any change being made to the memory content.
Caution: Once set, Write/erase protection can never be removed. A write-protected flash device is no
longer reprogrammable.
ICC connector
ICCDATA
ICCCLK
RESET
V
DD
HE10 connector type
Application
power supply
1
246810
975 3
Programming tool
ICC connector
Application board
ICC Cable
ST7
Optional
Application
reset source
Application
I/O
(See Note 5)
CLKIN/PB4