ST STM32C0 Option Bytes Programming

STM32C0 Option bytes programming and RDP locking/unlocking features are implemented in the PCode_DevPro_ST_STM32C0.pex script file.

Important notes

1. Performing RDP level 1 unlocking starts regression sequence. Flash memory is completely erased in this case.
2. Setting RDP to level 2 permanently locks the device. No unlock/regression possible.

Usage

DevPro -operation [operation_name] -if SWD -speed 4000 [parameter_name=value] -ScriptFile PCode_DevPro_ST_STM32C0.pex

Operation	Parameters	Values	Description
ReadOptionBytes	OptionName	FLASH_OPTR	Read FLASH option register.
		FLASH_PCROP1ASR	Read FLASH PCROP area A start address register.
		FLASH_PCROP1AER	Read FLASH PCROP area A end address register.
		FLASH_WRP1AR	Read FLASH WRP area A address register.
		FLASH_WRP1BR	Read FLASH WRP area B address register.
		FLASH_PCROP1BSR	Read FLASH PCROP area B start address register.
		FLASH_PCROP1BER	Read FLASH PCROP area B end address register.
		FLASH_SECR	Read FLASH security register.
WriteOptionBytes	OptionName	FLASH_OPTR	Write FLASH option register.
		FLASH_PCROP1ASR	Write FLASH PCROP area A start address register.
		FLASH_PCROP1AER	Write FLASH PCROP area A end address register.
		FLASH_WRP1AR	Write FLASH WRP area A address register.
		FLASH_WRP1BR	Write FLASH WRP area B address register.
		FLASH_PCROP1BSR	Write FLASH PCROP area B start address register.
		FLASH_PCROP1BER	Write FLASH PCROP area B end address register.
		FLASH_SECR	Write FLASH security register.
	Value	0xXXXXXXXX	32-bit value to be written to the register specified in "OptionName" parameter.

Detailed description

ReadOptionBytes

• Reads and prints out description of the selected option-byte register.

WriteOptionBytes

• Writes selected option-byte register. Using hex value is recommended.

Note:

Writing FLASH_OPTR register is used to lock device. The least 8-bits represent device locking level:
Value 0xAA - Device not locked
Value 0xBB or other than 0xAA or 0xCC - Level 1 protection
Value 0xCC - Level 2 protection

• Unlocking device is performed by programming FLASH_OPTR register with value 0xXXXXXXAA, where X is don't care.

Examples

Reading option bytes register

Example

DevPro -operation ReadOptionBytes -if SWD -speed 4000 -SetConfigVal "OptionName=FLASH_OPTR" -ScriptFile PCode_DevPro_ST_STM32C0.pex
SEGGER Device Provisioner V8.80
Compiled Oct 22 2025 12:00:41
Command line: -operation ReadOptionBytes -if SWD -speed 4000 -SetConfigVal OptionName=FLASH_OPTR -ScriptFile PCode_DevPro_ST_STM32C0.pex
Firmware: J-Link V12 compiled Nov 10 2025 13:42:51
S/N: 602000001

J-Link log: Version: V1.00.0
J-Link log: STM32C091xx/92xx device found, ID: 0x0000044D
J-Link log: ===============================================================================================
J-Link log: FLASH_OPTR
J-Link log: Value: 0xFFFFFEAA
J-Link log: -----------------------------------------------------------------------------------------------
J-Link log: RDP
J-Link log: Value: 0x000000AA
J-Link log: Level 0, read protection not active
J-Link log: -----------------------------------------------------------------------------------------------
J-Link log: BOR_EN
J-Link log: Value: 0x00000000
J-Link log:  |-> Configurable brown out reset disabled, power-on reset defined by POR/PDR levels
J-Link log: -----------------------------------------------------------------------------------------------
J-Link log: BORR_LEV
J-Link log: Value: 0x00000003
J-Link log: BOR rising level 4 with threshold around 2.9 V
J-Link log: -----------------------------------------------------------------------------------------------
J-Link log: BORF_LEV
J-Link log: Value: 0x00000003
J-Link log: BOR falling level 4 with threshold around 2.8 V
J-Link log: -----------------------------------------------------------------------------------------------
J-Link log: NRST_STOP
J-Link log: Value: 0x00000001
J-Link log:  |-> Reset not generated
J-Link log: -----------------------------------------------------------------------------------------------
J-Link log: NRST_STDBY
J-Link log: Value: 0x00000001
J-Link log:  |-> Reset not generated
J-Link log: -----------------------------------------------------------------------------------------------
J-Link log: NRST_SHDW
J-Link log: Value: 0x00000001
J-Link log:  |-> Reset not generated
J-Link log: -----------------------------------------------------------------------------------------------
J-Link log: IWDG_SW
J-Link log: Value: 0x00000001
J-Link log:  |-> Software independent watchdog
J-Link log: -----------------------------------------------------------------------------------------------
J-Link log: IWDG_STOP
J-Link log: Value: 0x00000001
J-Link log:  |-> Independent watchdog counter is running in Stop mode
J-Link log: -----------------------------------------------------------------------------------------------
J-Link log: IWDG_STDBY
J-Link log: Value: 0x00000001
J-Link log:  |-> Independent watchdog counter is running in Standby mode
J-Link log: -----------------------------------------------------------------------------------------------
J-Link log: WWDG_SW
J-Link log: Value: 0x00000001
J-Link log:  |-> Software window watchdog
J-Link log: -----------------------------------------------------------------------------------------------
J-Link log: HSE_NOT_REMAPPED
J-Link log: Value: 0x00000001
J-Link log:  |-> Disable
J-Link log: -----------------------------------------------------------------------------------------------
J-Link log: RAM_PARITY_CHECK
J-Link log: Value: 0x00000001
J-Link log:  |-> Disable
J-Link log: -----------------------------------------------------------------------------------------------
J-Link log: SECURE_MUXING_EN
J-Link log: Value: 0x00000001
J-Link log:  |-> Enable
J-Link log: -----------------------------------------------------------------------------------------------
J-Link log: NBOOT_SEL
J-Link log: Value: 0x00000001
J-Link log:  |-> NBOOT0 option bit
J-Link log: -----------------------------------------------------------------------------------------------
J-Link log: NBOOT1
J-Link log: Value: 0x00000001
J-Link log:  |-> NBOOT1 = 1
J-Link log: -----------------------------------------------------------------------------------------------
J-Link log: NBOOT0
J-Link log: Value: 0x00000001
J-Link log:  |-> NBOOT0 = 1
J-Link log: -----------------------------------------------------------------------------------------------
J-Link log: NRST_MODE
J-Link log: Value: 0x00000003
J-Link log: Reserved
J-Link log: -----------------------------------------------------------------------------------------------
J-Link log: IRHEN
J-Link log: Value: 0x00000001
J-Link log:  |-> Internal resets drives NRST pin low until it is seen as low level
J-Link log: -----------------------------------------------------------------------------------------------
J-Link log: FDCAN_BL_CK
J-Link log: Value: 0x00000003
J-Link log: HSE crystal - 48 MHz
J-Link log: ===============================================================================================

Writing option bytes register (setting RDP level 1 protection)

Example

DevPro -operation WriteOptionBytes -if SWD -speed 4000 -SetConfigVal "OptionName=FLASH_OPTR" -SetConfigVal "Value=0xFFFFFEBB" -ScriptFile PCode_DevPro_ST_STM32C0.pex
SEGGER Device Provisioner V8.80
Compiled Oct 22 2025 12:00:41
Command line: -operation WriteOptionBytes -if SWD -speed 4000 -SetConfigVal OptionName=FLASH_OPTR -SetConfigVal Value=0xFFFFFEBB -ScriptFile PCode_DevPro_ST_STM32C0.pex
Firmware: J-Link V12 compiled Nov 10 2025 13:42:51
S/N: 602000001

J-Link log: Version: V1.00.0
J-Link log: STM32C091xx/92xx device found, ID: 0x0000044D
J-Link log: Option bytes programmed successfully