How to put the nrf52832 into deep sleep mode

[Sami]

Hello,

I am currently using nRF52832 with SDK v11.0.0 and S132 v2.0.0. I am also using the soft device as my application requires. I have been trying to put the CPU into SYSTEM OFF mode using the following:

// Configure the "main" button:

nrf_gpio_cfg_sense_input( BUTTON_MAIN_PIN, NRF_GPIO_PIN_PULLUP, NRF_GPIO_PIN_SENSE_LOW );

// Enter SYSTEM OFF mode

sd_power_system_off();

There is one major problem -- the system is still pulling a lot of current ~3.5mA. I don't understand what is going on. I read this in the manual, in section 18.2: "

Before entering System OFF mode, the user must make sure that all on-going EasyDMA transactions have been completed. This is usually accomplished by making sure that the EasyDMA enabled peripheral is not active when entering System OFF. "

Questions: -Am I using the correct function call for my version of the SDK to put the system in System OFF mode?

                  - Is the EasyDMA consuming that much current?! If so, how do I disable EasyDMA and ensure all transactions are complete?

                   - What other calls am I missing?

[Simonr]

Hi

What peripheral(s) is your application using with EasyDMA? The current consumption you are seeing looks more like your chip is in debug mode. You should always be able to go back to normal mode by way of a reset, try adding NRF_POWER->RESET =1; to your code, from here, you should be able to do pin reset after programming.

Best regards,

Simon

[Sami]

Hi Simonr, thank you for your reply. My application is running I2C and SPI which both are using EasyDMA. I thought that if I turned off EasyDMA but uninitializing the I2C driver and SPI driver, everything would be ok. 

Is sd_power_system_off() the correct function call to make?

I'm using the nRF52832, not the nRF52811 (which is the model number that your debug mode link sends me to).

My application must be put into System OFF mode via user interaction, and not after a reset.

So do I call 

NRF_POWER->RESET =1;

and then 

sd_power_system_off(); ?

Thank you.

[Sami]

NRF_POWER->RESET = 1; // this does not exist in SDK 11.0.0

Please advise how to put the system into Debug mode before I call sd_power_system_off()

[Simonr]

You can also use sd_nvic_SystemReset() at the start of your main() function. This should work in SDK 11.0.0 as well.

The problem could be the EasyDMA, but I want to eliminate this possibility before going down that road. You want to get out of Debug mode, not into it.

Best regards,

Simon

[Sami]

Hi Simonr,

Thank you for your reply. I put sd_nvic_SystemReset() at the very start of my main() function (to take the system out of debug mode) and now my app doesn't run at all (completely unresponsive). Looks like there's another piece of information that I may be missing here...

For EasyDMA, I'm uninitializing + disabling all TWI and SPI resources before calling sd_power_system_off(). 

Thanks,

Sami