I try to dialog 2 boards through HDLC FM0 => MPC885 on both side.
(configuration , preambule 8 bits 0xFF, Glitch=OFF, Transparent mode=OFF, CRC=16 bits, TX=16 bytes, RX=32 bytes, X21=OFF, TBRTSM=0)
when i set the field TEND of GSMR_L to 1, ie. TXD is always encoded, even when idles are sent => no problem.
But when i set the field TEND to 0, ie. TXD is encoded only when data is sent , on Rx board side the MPC885 log the error AB and skip the check of CRC on each received frame.
The datasheet $23.3 says
Note that an SCC in HDLC mode, or any other synchronous mode, must receive a minimum of eight
clocks after the last bit arrives to account for Rx FIFO delay.
So i think when the TEND field is set to 0, 8 clock are automaticly sent but not with TEND set to 0 which is my problem.
To send a second closing flag or a postambule ( $23.3 adding 8 clock at the end) , i set the field NOF of the PSMR to 2.
Note NOF : Number of flags. Minimum number of flags between or before frames.
But in this case (NOF ==2) only the opening flagis impact (at least 2 opening flag) never for the closing flag (always 1).
Somebody can help me to add the 8 clock at the end of closing flag ?