[riot-devel] Re-transmission, interval 40ms problem

Peter Kietzmann peter.kietzmann at haw-hamburg.de
Tue Jan 30 16:19:07 CET 2018

Hi Baptiste,

see the following extract of the AT86RF233 datasheet [1]:

> If no valid ACK is received or after timeout of 54 symbol periods (864μs), the radio
> transceiver retries the entire transaction (CSMA-CA based frame transmission) until the
> maximum number of frame retransmissions is exceeded, see register bits
> MAX_FRAME_RETRIES (register 0x2C, XAH_CTRL_0). In that case, the
> TRAC_STATUS is set to NO_ACK, the TX_ARET transaction is terminated, and
> interrupt IRQ_3 (TRX_END) is issued.

IIRC the max. number of retransmissions with that device in RIOT is 3
retries after missing ACK and 4 retries (including random backoff) after
denied channel access.

If you need further help, please point to a specific branch or commit to
reproduce that behavior.


Am 30.01.2018 um 13:31 schrieb Baptiste Clenet:
> How does CSMA work on at86rf2xx driver?
> Is error handled?

Peter Kietzmann

Hamburg University of Applied Sciences
Dept. Informatik, Internet Technologies Group
Berliner Tor 7, 20099 Hamburg, Germany
Fon: +49-40-42875-8426
Web: http://www.haw-hamburg.de/inet

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