Using PPI with Zboss zigbee stack

RE: Using PPI with Zboss zigbee stack

Jørgen Holmefjord — Fri, 10 Feb 2023 13:28:43 GMT

Did you enable the PPI channels in your application before or after initializing the Zigbee stack?

I'm not sure if all channels are used by the 802.15.4 driver in all states, the channel may not be used at the point where you tested. You can see how the channels are used in the driver source. There is also a define you can use to mask out the used channels.

RE: Using PPI with Zboss zigbee stack

Gueston — Wed, 08 Feb 2023 10:46:12 GMT

By the way: I discovered when I add for instance 0x1F as a mask to the NRF_PPI_CHANNELS_USED, I read in the log that it uses PPI channel 10. Then it works, but according to that list the zigbee stack is using PPI 0-12, so how can PPI channel 10 work?

RE: Using PPI with Zboss zigbee stack

Gueston — Tue, 07 Feb 2023 15:47:09 GMT

Adding that awareness indeed solved the problem. Shouldn't this be added by default?

RE: Using PPI with Zboss zigbee stack

Jørgen Holmefjord — Mon, 06 Feb 2023 15:41:02 GMT

Hi,

The PPI 0-5 channels are only used by the 802.15.4 radio driver if debugging of radio events on GPIOs are enabled (by ENABLE_DEBUG_GPIO symbol). As far as I know, this is not enabled by default in the Zboss stack. It should therefor be ok to use the PPI channels for other purposes.

I'm not sure if the nrfx_ppi driver is aware of the PPI channels used by Zigbee stack, I could not find any sources in the SDK that specify channels used by this stack (we have defines for the Softdevice and ESB/Gazell protocols). You can add awareness of the PPI channels used by Zigbee stack by modifying sdk_resources.h to include PPI channel mask for used channels in NRF_PPI_CHANNELS_USED define.

Best regards,
Jørgen