RE: nRF52840 RAM Retention in System ON Mode

Vidar Berg — Fri, 12 Oct 2018 09:03:28 GMT

Hello Mark,

Unused RAM sections can be power down in system ON mode (RAM power control). So no RAM retention in System ON means that all blocks are powered off with retention disabled. Here is an example of you can power down all RAM blocks (replace with softdevice API if softdevice is enabled):

NRF_POWER->RAM[0].POWERCLR = 0x3; //See memory section in PS for number of RAM sections in each block.
NRF_POWER->RAM[1].POWERCLR = 0x3;
NRF_POWER->RAM[2].POWERCLR = 0x3;
NRF_POWER->RAM[3].POWERCLR = 0x3;
NRF_POWER->RAM[4].POWERCLR = 0x3;
NRF_POWER->RAM[5].POWERCLR = 0x3;
NRF_POWER->RAM[6].POWERCLR = 0x3;
NRF_POWER->RAM[7].POWERCLR = 0x3;
NRF_POWER->RAM[8].POWERCLR = 0x3F;

for(;;)
{
__WFE();
}

Best regards,

Vidar