question about USART change its baud rate during the process

cchappyboy · Joined: 03 Dec 2008 Posts: 45

How can I change baud rate after I received data and change back again after send out and so on ? For example the USART set to #use rs232(baud=9600, xmit=pin_c6,rcv=pin_c7) and I used interrupt to receive data. After I got enough data I want to send out data but need different baud rate for example #use rs232(baud=4800, xmit=pin_c6,rcv=pin_c7) what should I do. Do I need disable interrupts and after initial enable it again?

I am appreciate for any concern...

rwskinner · Joined: 08 Dec 2006 Posts: 125 Location: Texas

I change the Usart register values on the fly.

Check the USART registers, mainly SPBRG...
This is for a 877 running at 20 Mhz if I remember correctly.
PBP Code....

SELECT Case Tmp
Case 0 '57,600 SEE NOTE ON & ON
SPBRG = 21

CASE 1 '38400 ON & OFF
SPBRG = 32

CASE 2 '19,200 OFF & ON
SPBRG = 64

Case 3 '9600 OFF & OFF
SPBRG = 129

End;

PCM programmer · Joined: 06 Sep 2003 Posts: 21708

Download the CCS manual.
http://www.ccsinfo.com/downloads/ccs_c_manual.pdf
Look in this section. It has a list of CCS functions that handle RS-232: