maximum QDEC sample frequency

[sebastiano.xinet]

Hi everyone! We're working with the processor nRF51422 with S210 softdevice and we've found an issue about the QDEC sample frequency. In fact, the minimum sample period by configuring SAMPLEPER=0 is 128us, but in our project we have an encoder that reach at its maximum speed, period around 90-100us, and sometimes in this conditions, QDEC can't sample in the correct way. So my question is: is it possible to have a faster sample frequency? For example the half of the current min period of sampling: a period around 64us could be enough for our purpose. Thank you.

[RK]

No it's not - the spec sheet for the nrf51x22 tells you the minimum sampling period for the QDEC is 128µs. That's it, that's the minimum.

[sebastiano.xinet]

Yes, we had already seen what spec sheet tells but we had also seen that the debounce filter, that is into the process of QDEC, work with a 1MHz sampling frequency. So, our question meant to ask if could be an alternative way to use that frequency also for the QDEC sample. Thank you.

[ovrebekk]

As mentioned there are no quicker modes available unfortunately.
If you need to reliably detect a pulse quicker than this you would probably have to do it using the GPIOTE, PPI and TIMER modules, but that would make for a significantly more complex implementation.
I assume the movement is bi-directional (like a scroll wheel for mice) ?

[sebastiano.xinet]

Yes, the movement is bi-directional. If other ways are much more complex to implement we'll use some external device to resolve our problem. Thanks anyway for the reply.

[ovrebekk]

If an external device is an option that would probably be best. I am sure you could hack something together with the nRF51 alone, but I doubt it would be a 100% reliable solution ;)