jtroxas wrote:

I am finding myself wanting to repeat Olin's rant about people not wanting 
to answer relevant questions. :)

> no just the 4-5 last bytes... I think its in the way I'am clearing\setting 
> the RTS\CTS lines in the pic and PC ie.. I am doing it too early both from 
> the PC and PIC side( Iam doing RTS\CTS manualy in code immidiately after 
> the last byte is written to the USART TXREG PIC side and similar thing on 
> the PC side)...

That's definitely the wrong way to do it. If you absolutely *need* to use 
handshaking lines, you disable the line only after you check the flag that 
tells you the message was sent, not after you put your last byte into TXREG.

> but since it takes time for the data to be shifted out from the 
> USARTshiftregisters and the data from TXREG be sent to the output 
> shiftregister to be again shifted out and sent to the PC.. the PC will 
> never received the 2 last bytes in the PIC's USART transmit buffer(TXREG 
> and SHIFT REgister) because the signal that say Finished Transmitting is 
> already seent just after writing the last byte to TXREG... the same thing 
> happens from the PC side when transmitting so another 2-3 bytes is lost 
> from the PC transmit buffer..

Are you controlling the PC handshake lines *directly*?

> I think the solution is to add some waiting time before setting/clearing 
> RTS\CTS(make sure that buffers are really empty).. but waiting a few 
> milliseconds is a little costly(PIC is doing nothing) so I managed to try 
> a hack and just add some null bytes to the end of every data I send, 
> expecting that it will be trimmed out.. and remove the waiting code.. 
> after all I am using interrupts for Transmit and receive..

Sounds like an ugly hack. Read the datasheet -- you have two useful flags at 
your disposal, which tell you exactly when the TXREG or the TSR registers 
are empty. Namely, the TXIF and TRMT flags.

Vitaliy 

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