GZLL host not responding to more than 3 pipes

[sean]

I am trying to set up a GZLL star network on the 51822. I understand that a single GZLL host can support up to eight devices but whenever my host attempts to communicate with more than 2 devices each communicating under a unique pipe the host controller seizes. It is still receiving packets from the other devices but it is unable to add any ACK packets to its tx fifo buffer.

Are there any examples of a host that will communicate with 8 devices simultaneously? Am I correctly understanding that each device should communicate via its own pipe?

[Håkon Alseth]

Hi,

It is correct that each device shall communicate with the host using an unique pipe. If you setup two devices on the same pipe (ie: same RF address), you will get a collision and your communication will not work properly.

If I understand correctly, the communication works with 8 devices -> 1 host, but the ACK payload is unreliable? If yes, could you please elaborate on what's happening?

Note that the host only has a 3 payload deep buffer in the FIFO. This means that if you upload 3 payloads on one pipe, where the device seldom sends payloads to the host (device does not poll the host often enough compared to other devices), you will use up all the space and block other devices from receiving an ack-payload.

In general; it is very important to check your error codes given by the gazell function calls to see if there is anything that's failing.

Cheers, Håkon

[sean]

Thank you for your response Håkon. I am using the example project "gzll_ack_payload". I have one programmed with the host firmware and three programmed with the device firmware. The pipe in each of the devices is set to 0, 1, and 2.

I power up the host first. I then power up device with pipe 0 and everything is fine. I then power up device with pipe 1 and everything is fine. The moment I power up the device using pipe 2, all communications cease. This works invariably with the devices powering up in any order (e.g. If I power up 1 and 2 first and pipe 0 last then everything freezes when pipe 0 comes online).

EDIT: It seems the host is returning errors on 'nrf_gzll_add_packet_to_tx_fifo'. The error return value corresponds to NRF_GZLL_ERROR_CODE_INSUFFICIENT_PACKETS_AVAILABLE. This only happens when the third pipe tries to communicate with the host.