RAM and OFF mode

[larry]

hi, i have kept RAM block 0 and RAM block 1 on in OFF mode by calling "sd_power_ramon_set(0xf000f)" before entering off mode ,i saw the value of RAMON register is 0x00030003 by simulating.but RAM will be clear after entering OFF mode,who can tell me the reason , i knew RAM will not reset after soft reset ,but variable will be initialized after soft reset,i want to keep value of some variable after Soft reset and Wakeup from OFF mode reset,so How I should do.

[Håkon Alseth]

Hi,

Did you read using sd_power_ramon_get() to verify that it's set properly? Regarding clearing of RAM on wakeup: The startup script will clear sections of RAM unless stated so in the attributes when declaring the variable. Syntax for keil is: static uint32_t myvar __attribute__( ( section( "NoInit"), zero_init) );

Best regards Håkon

System OFF_noinit.zip

[larry]

thanks for your swift reply, i used the routine you gived , under the condition of i did not use softdivce ,my varaible can be saved when waking up.but my variable will be clear when i use s110 v6.Why is this so.

[Håkon Alseth]

When using the softdevice, the second ram-block is used for the application. Make sure that both RAM-blocks are being powered under systemoff using sd_power_ramon_set(). Please see the nRF51 reference manual for which bits you should set in the register.

[Anand Ramashetty]

what is the syntax in GCC environment