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

[Ernst Stippl]

Hi Manuel! 

Maybe the weird "0" you are receiving is created by the "turnaround" of the
transmission direction on the RS485 link? Are you receiving the "0" for
every character sent? How is the echo done on the client side? Is each
character echoed immediately when received by the client or is the text
received and stored upto a cr/lf and the sent back by the client?

regards 
ernst

-----Ursprüngliche Nachricht-----
Von: en-nut-discussion-bounces at egnite.de
[mailto:en-nut-discussion-bounces at egnite.de] Im Auftrag von Manuel Mausz
Gesendet: Dienstag, 18. April 2006 17:56
An: Ethernut User Chat (English)
Betreff: RE: [En-Nut-Discussion] Receiving weird 0 on UART

I've just noticed that the list has deleted my attachment.

Test prog @ http://www.netcore.at/misc/test.c

/ manuel

> -----Original Message-----
> From: en-nut-discussion-bounces at egnite.de
> [mailto:en-nut-discussion-bounces at egnite.de]On Behalf Of Manuel Mausz
> Sent: Monday, April 17, 2006 5:56 PM
> To: en-nut-discussion at egnite.de
> Subject: [En-Nut-Discussion] Receiving weird 0 on UART
>
>
> 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
>

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