RE: Re: UART Communication between MPC566 and a 8bit Microcontroller

THe sci baud rate is actually derived from the IMB clock and not the
system clock.  It sounds like you have HSPEED set (UMCR register) thus
IMB clock would be 20MHz.  Most of the peripherals timing is based on
the IMB clock.
 
- Allan

________________________________

From: [email protected] [mailto:[email protected]] On Behalf
Of Rajesh
Sent: Friday, September 29, 2006 10:58 AM
To: [email protected]
Subject: [MPC500] Re: UART Communication between MPC566 and a 8bit
Microcontroller




Hi Joe,
The configuration part is ok. Now I found a small fault in
this. I captured the time required for transfer/receive of each data
bits on CRO, by sending a dummy character through SCI; and this bit
trnsfer/rcving time is matching with baudrate of 9600,whereas my code
is running on 19200,i.e. exactly on double.
I have also checked the MPC566 clock frequency which is 40MHz and
crystal is running at 4MHz. The relation between SCI baud rate and
system-clock frequency as mentioned in datasheet is :
= fsys/(32*baudrate), whereas,
fsys is 40MHz and 
bautrate = desired baud rate of operation (19200 in mycase).

Can you please tell,why it is wroking exactly at half baudrate,though
I have configured as 19200? Is there any problem of some division
factor,that is taken care internally?

-regards
Rajesh 

--- In [email protected] <mailto:MPC500%40yahoogroups.com> ,
"trailrunner23" <joep@...> wrote:
>
> Hi Rajesh,
> 
> The two UARTs must be configured with the same settings to communicate
> with each other:
> 
> - baud rate, data bits, parity, stop bits
> 
> If you have them set up the same way, and they are not communicating,
> you must be doing something else wrong.
> 
> Joe
> 
> --- In [email protected] <mailto:MPC500%40yahoogroups.com> ,
"Rajesh" <rajesh86us@> wrote:
> >
> > 
> > Hi,
> > I am using two microcontrollers, one is MPC566 with 40 MHz
> > clock,and other one is a 8 bit,running at 22.1184 MHz. I am trying
for
> > (OnBoard) inter-processor UART communication,by running MPC at a
> > baudrate of 19200 and the other at 9600. 
> > The problem is, sometimes it runs and data Trasmission and Recieving
> > is ok, but sometimes it's not.
> > I tried by configuring both with same baud rates but geting same
> problem.
> > Can anyone please suggest,how to deal with this problem?
> > 
> > -regards
> > Rajesh
> >
>



 


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