Sram Erase; Table 2. Sram Erase Conditions - STMicroelectronics STM32WLEx Reference Manual

RM0461
The following memories can be remapped:
•
Main flash memory
•
System flash memory
•
SRAM memory
Embedded bootloader
The embedded bootloader is located in the system flash memory, programmed by
STMicroelectronics during production. It is used to program the flash memory using one of
the following device interfaces:
•
USART1 on pins PA9 and PA10
•
USART2 on pins PA2 and PA3
•
SPI1 on pins PA4, PA5, PA6 and PA7
•
SPI2S2 on pins PB12, PB13, PB14 and PB15
The embedded bootloader runs on the CPU and can be used to load content in memory
areas.
2.3

SRAM erase

SRAM1, SRAM2 and PKA SRAM provide an SRAM erase feature.
These SRAMs are erased under the conditions detailed in the table below.
Condition
(3)
System reset (user option SRAM_RST = 1)
System reset (user option SRAM_RST = 0)
OBL with invalid user options
RDP regression from 1 to 0, on OPTSTRT.
Tamper
SYSCFG_SCSR SRAM2ER
1. An ongoing SRAM1 or SRAM2 erase can be monitored by SYSCFG_SCSR.SRAMBSY flag.
2. An ongoing PKA SRAM erase can be monitored by SYSCFG_SCSR.PKASRAMBSY flag.
3. POR, NRST and wakeup from Standby.
4. For more details, see Table 12: RDP regression from level 1 to level 0 and memory
5. To be able to debug without SRAM erase on tamper, especially ITAM6 debug access, the tamper erase must be disabled in
the TAMP by firmware.

Table 2. SRAM erase conditions

(5)
RM0461 Rev 5
(1)
SRAM1
Retained
Hardware erased Hardware erased
Hardware erased Hardware erased
(4)
Hardware erased Hardware erased
Retained Hardware erased
Retained Hardware erased
Memory and bus architecture
(1)
SRAM2 PKA SRAM
Retained Hardware erased
Hardware erased
Hardware erased
Hardware erased
Hardware erased
Retained
erase.
(2)
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