STR7:

 

1. Protection:

STR7 series microcontrollers from STMicroelectronics use a Flash Read Out Protection (ROP) mechanism. This protection is controlled by a single bit in a special memory area called the Option Byte.

 

1.1 Read Out Protection (ROP):

When ROP is enabled, any access to the main Flash memory via the debug port (JTAG) is blocked. This prevents unauthorized reading, modification, or erasing of the firmware using external programmers. However, the ARM7TDMI-S core can still execute code from the protected memory.

Protection States:

ROP State Description Disabled (0xFF in Option Byte) Protection is disabled. Access to Flash via JTAG is allowed. Enabled (any value other than 0xFF) Protection is enabled. Access to Flash via JTAG is blocked.

 

1.2 Disabling Protection:

Disabling the read protection is a destructive operation. The only way to disable ROP is to trigger a Mass Erase of the entire Flash memory. This is done by reprogramming the Option Byte to the unprotected state (0xFF).

WARNING: This operation completely and irreversibly erases the entire user program in the Flash memory. After the erase, the microcontroller returns to an unprotected state, ready for new programming.

 

1.3 Write Protection:

In addition to ROP, the Flash memory in STR7 can be write-protected on a per-sector basis. This allows protecting specific areas, such as a bootloader, from accidental or intentional modification by the main application. This protection does not prevent reading via JTAG if ROP is disabled.

 

2. Unique Identifier:

STR7 series microcontrollers do not have a unique 96-bit ID for each die, unlike the later STM32 series. Device identification is only possible through the Device ID register, which is the same for all chips of the same model (e.g., STR711).

 

STMicroelectronics (STR7 MCUs)

 

Ask your question: RussianSemiResearch@ya.ru

 

 
RussianSemiResearch. © 2008-2025.E-mail: RussianSemiResearch@ya.ru