The SUPC can be used to switch on or off the power supply of the backup SRAM by opening or closing the SRAM power switch. This power switch is controlled by SUPC_MR.BKUPRETON. However, the battery backup SRAM is automatically switched on when the core power supply is enabled, as the processor requires the SRAM as data memory space.
- If SUPC_MR.BKUPRETON is written to ‘1’, there is no immediate effect, but the SRAM will be left powered when the SUPC enters Backup mode, thus retaining its content.
- If SUPC_MR.BKUPRETON is written to ‘0’, there is no immediate effect, but the SRAM will be switched off when the SUPC enters Backup mode. The SRAM is automatically switched on when Backup mode is exited.