Author:  saw
Date:  07-17-96
Comments:  Initial Version
Date:  03-31-97
Comments:  Added Tables in C header file format

README for Asynchronous Communication Baud Rate Tables:

This directory contains baud rate tables, similar to those found in Section 13.13.3,
Table 13-9 of the MPC821 Spec, Version 0.4.  Table 13-9 is extended to provide
baud values for the following system frequencies (in MHz):  20, 24, 24.576, 25,
28, 30, 32, 35, 36, 40, 44, 45, 48, 49.9712, 50.

These tables are contained in an Excel spreadsheet and C header file format.


The Asynchronous Baud Rates are calculated according to the following formula:
-------------------------------------------------------------------------
Async Baud Rate = (System Clock) / ((Div + 1) * (DivBy16) * (Internal Clock Factor))

Div corresponds to the column of clock divider values in the Baud Rate Tables.

DivBy16 = 16 if Div16 bit==1; 1 otherwise.

Internal Clock Factor = 8 or 16 or 32 according to RDCR and TDCR bits in SCC Mode Register.
The value used here is 16 -- the internal clock rate is assumed to be 16x the baud rate.
The format of the tables file is Microsoft Excel Worksheet, Version 4.0.
-------------------------------------------------------------------------

The BRGCx Register is initialized as follows:
-----------------------------------------
BRGCx = 0x10000 | (Div << 1) | Div16
The 0x10000 enables the BRGCx counter.
-----------------------------------------

>> PLEASE READ <<
NOTES:
(1)  The Baud Rate Tables are for use with asynchronous communication.
(2)  The Internal Clock Rate is assumed to be 16x the Baud Rate.  If this value is 
       different on your system, then the Baud Rate Values, as presented, are invalid.
(3)  The factor in (2) can be obtained from the RDCR and TDCR bits in the SCC Mode Register.

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Baud Rate Tables File List:
1) baud.xl -- Baud Rate Tables file.
2) baud.h -- C Header file of asynchronous baud rate settings.
3) README -- This file.

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