SV: SV: [Icc-avr] Debug using Jtag

[John Baraclough]

Hi Steven,

Yes, that's a tricky one. The TXC interrupt flag 
is set every time a complete character is 
transmitted, regardless of whether there is 
another character waiting in the buffer. What you 
have to do is clear the TXC flag every time you 
hit the UDRE interrupt and only enable the TXC 
interrupt in the UDRE interrupt handler once 
there are no more characters to be sent. As the 
RS485 can be switched very quickly, it is also a 
good idea to add an extra stop bit to the last transmitted character.

You're welcome to contact me directly if you need any more help.

All the best for now,
John


At 10:26 28/09/2007, you wrote:
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>Content-Type: multipart/alternative;
>         boundary="----_=_NextPart_001_01C801B1.B41FA12D"
>
>Hi.
>
>I got a little further, and found out that The 
>write seems to be the legal function anyway, I 
>just didn't caught it because TXC complete int. 
>is getting served before the Tx Buffer is empty.
>
>In 0.003% of the transmissions, as soon as the 
>UDRE interrupt is finished filling the last 
>bytes in Txbuffer and disables itself, TXC int 
>is served before buffer is finished transmitting.
>
>Result is that the last or the 2 last bytes in 
>Txbuffer is not transmitted because TXC sets the 
>RS485 driver back in Input mode.
>
>So now I just have to find out why!
>It's nothing but fun.
>
>Med venlig hilsen / Best regards / mit freundlichen Grüßen
>
>EC POWER A/S
>
>Steven Lose
>
>Software Ingeniør
>
>Tlf.: +45 87434100
>
>Direkte tlf. +45 58286608
>
>Email: sl at ecpower.dk
>
>www.ecpower.dk
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