[En-Nut-Discussion] Receiving weird 0 on UART

[Manuel Mausz]

Hi list,

we're currently building a client<->server application and therefor we're using the ethernut 1.3 rev. F board (as server). To
communicate with the other selfmade boards(/clients), we're using a SN75176BP to convert from RS232 to RS485.

For testing purpose our client board is just echoing all characters. If we run the attached test program without the RS485 driver,
everything works as expected. But if we add the driver and ethernut is sending characters first (line 114), we always receive a 0
before we get the sent characters. If we run another test program which only let the client board send data, we don't get any 0s.

Since we're stuck now, any input would be appreciated.

Setup:
Driver SN75176BP:
PIND5 -> ^RE/DE
PIND2(RX) -> R
PIND3(TX) -> D

Ethernut 4.1.3
UART1_HDX_BIT = 5
UART1_HDX_AVRPORT = AVRPORTD

Regards,
/ manuel