sleep function is not working when timer/RTC is running in nRF51822

[adrianwong]

nrf51822_sleep_and_timer.txt

Hi... I having tough time to make the sleep function to work when timer/RTC is running in the background of nRF51822. The attached text file containing my code. After comment out the start_timer() & start_RTC() in the setup() then the sleep function is working fine as I will only can be woke up by the external internal. If either one of this function : start_timer() or start_RTC() is uncommented from the setup() then the system is not going to sleep as I got to know it by checking on the serial monitor as it's keep on printing "Hello". Kindly assist. Thanks.

[Susheel Nuguru]

Hi adrianwong,

I did not see the code where you calling your loop or sleep functions, but i assume you do it somewhere.

You timer is programmed to generate an interrupt every 0.5ms, which is 2000/second. Which is very fast, so even if your system sleep, waking it up every 0.5ms and trying to do some interrupt handling/printing that takes some time.

Your system is still going to sleep, you cannot see it because it wakes up so frequently that you cannot judge it from the print log.

[adrianwong]

Hi Aryan, I totally understand what you trying to explain to me. I still wondering is this Nordic characteristic? Nordic cannot sleep completely and run timer/RTC on the background. Because I try it out with Atmel chip again with the code that I have, and the sleep doesn't woke up by the timer/RTC interrupt. The timer able to run at the background and the system still able to sleep. Why I know is sleeping because i put printf some string on the main loop and ntg is printing out. The system will only be woke up by the accelerometer interrupt then i only can see the printf string. Kindly assist.