nRF51822 PWM strange behavior

RE: nRF51822 PWM strange behavior

Vrabec — Tue, 29 Sep 2015 18:40:19 GMT

Thank you for detailed explanation. I already ordered nRF51822 rev. 3.

RE: nRF51822 PWM strange behavior

Stefan Birnir Sverrisson — Tue, 29 Sep 2015 12:14:56 GMT

You are correct. The compatibility matrix states that S110 8.0.0 has been tested with nRF51 second revision, but SDK 7+ has not been tested with nRF51 second revision and is not implemented for the second revision. SDK 7+ might not implement workaround for anomalies stated in the PAN document for second revision nRF51. To realize what changes has been made from second to third revision nRF51, look at the PCN document that describes that. You can see what PAN and PCN documents to look at in table 3 in the compatibility matrix.

My advise, it is easier to get a third revision nRF51, unless you mean to update existing product in the field that contains nRF51 second revision devices. Is that your situation?

RE: nRF51822 PWM strange behavior

Vrabec — Mon, 28 Sep 2015 15:55:49 GMT

In compatibility matrix (table 4) I notice, there nRF51822 2nd rev. supports S110 ver. 8.0.0 but there is SDK missing. It's possible to use SDK 7+ or this version of softdevice can not be used on 2nd rev. at all?

RE: nRF51822 PWM strange behavior

Stefan Birnir Sverrisson — Mon, 28 Sep 2015 15:19:44 GMT

Yes, I aggree that you have second revision nRF51 with QFAAG0 chip markings. You should use third revision nRF51 as that is compatible with SDK 7+, see the nRF51 compatibility matrix table 4

RE: nRF51822 PWM strange behavior

Vrabec — Sun, 27 Sep 2015 18:02:31 GMT

I'm using latest SDK (9.0.0). The marking on chip is: N51822 GFAAG0 1407AV what based on compatibility matrix and forum responses seems to be 2nd revision.

RE: nRF51822 PWM strange behavior

Stefan Birnir Sverrisson — Fri, 25 Sep 2015 08:10:45 GMT

The latest nrf_pwm library is to use with SDK 7.0.1+. Are you using SDK 7.0.1 or later?

What are the chip laser markings on the nRF51 chip on your module? That should say something about if it is second or third revision nRF51, see the nRF51 compatibility matrix

RE: nRF51822 PWM strange behavior

Vrabec — Thu, 24 Sep 2015 16:32:38 GMT

I'm using Keil uVision. I started with latest version of PWM example through uVision's Pack Installer. This works fine (I'm not using softdevice for now), however I read using this PWM and Softdevice at once can lead to problems. Therefore I download and import latest version of nrf_pwm. In addition, I'm not using DK but this. Hopefully my answer somehow helps.

RE: nRF51822 PWM strange behavior

Stefan Birnir Sverrisson — Thu, 24 Sep 2015 12:16:48 GMT

Hi Vrabec

Thank you for your question.

I can not reproduce the issue with your code, using nrf_pwm.h, SDK 7.0.1 and nRF51-DK. What SDK version and hardware are you using?

RE: nRF51822 PWM strange behavior

Vrabec — Mon, 21 Sep 2015 19:09:34 GMT

I don't find reason why this happened, but using nrf_pwm_noglitch solves the issue. But anyway it can be useful to know what is wrong in nfr_pwm libraby.