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.

[Susheel Nuguru]

I do not know much about ATMEL chips and how you configure it, but any processor cannot be sleeping and still be able to run its interrupt handler. Processor has to wake up to process its enabled interrupts and then run its interrupt handler.

If you want that accelerometer interrupt is the only only one that wakes your system , then you need to disable RTC interrupt. I can't say why the same thing worked on ATMEL.