RE: nRF51822 SPI limitations (send/recv from timer)

muhkuhns — Fri, 26 Jun 2015 13:04:35 GMT

I worked around this by just setting a flag when the timer expires and putting my actual code (+unset flag of course) inside an if(flag)-statement inside the main-loop.

This works fine for me. The cpu can also go to sleep. It checks in the main-loop if the flag is set, if not it goes to sleep. When the timer expires and the flag was set in the timer event handler the flag in the main-loop is checked again and executed and the cpu goes back to sleep again.

RE: nRF51822 SPI limitations (send/recv from timer)

Krzysztof Chruscinski — Fri, 26 Jun 2015 12:57:26 GMT

Hi,

are you using SPI driver from SDK (if yes then from which version?).

In general there is no such limitation, only that if you are using SoftDevice from time to time you might get bigger gaps between bytes in the transfer because SPI interrupt has bigger latency (if SoftDevice processes the stack).

If you have SoftDevice you must ensure that calls to SoftDevice does not happen from application high interrupt level because you will get deadlock (SVC call to SoftDevice on lower priority). SPI driver from SDK is calling softdevice API so it might be the case that your context has too high priority.