Eduardo Estigoni

MC9S08 GT60 : SCI BAUD RATE

Discussion created by Eduardo Estigoni on Aug 31, 2007
Latest reply on Sep 19, 2007 by Ross Myers
Hi Guys,

I've been doing some tests with the baud rate configuration of the SCI using a MC9S08 GT60.
All the setup was made, and I'm now only changing the value of the register SCI1BDH and SCI1BDL...

In the board, I'm using an FTDI chip to do the USB stuff and them send data to the PC...

My application on the PC is a C++ software, and the communication is just fine (using FTDI drivers) when I use baud rates lower than 34800. That means, I send one byte on the board and get it imediately on the C++ app.

However when I use higher Baud rates, what is happening is a sort of "buffering"... I still don't loose any byte, but the C++ app sees something on the queue only after 3968 Bytes. That means that I keep reading queue=0 and then sudenly I get queue=3968!!


Neither the mcu nor the FTDI chip is supposed to limit the baud rate to 34800... And I already tested in 2  PCs,  being one of them a Dell dual core brand new...


Does anybody have a clue of what that could be?

Thanks in advance,

Ed.

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