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, previously when I wrote my code and upload to Atmel it was fine. The system went to sleep (might not be deep sleep), and the timer do it stuff at the back (e.g. counting a timer). The sleep mode was woke up by external interrupt (interrupt from accelerometer). If timer interrupt / RTC keep waking up the system based on time setting then it doesn't make sense to me. If I want to build a timer to calculate period of 60 mins at the background how should i do? If I want to use the low power RTC to blink the led for 1 seconds every hour then what should i do? kindly advice!