6.2 Baud Rate Generator Programming
The baud rate generator (hereafter referred to as the BRG) of the SCC consists of a 16-bit
down counter, two 8-bit time constant registers, and an output divide-by-two. The time constant
for the BRG is programmed into WR12 (least significant byte) and WR13 (most significant
byte). The equation relating the baud rate to the time constant is given below while Table 12
shows the time constants associated with a number of popular baud rates when using the standard
MPA-100 9.8304 MHz clock.

Baud_Const =

Clock_Frequency
2&Baud_Rate&Clock_Mode -2
Where:
Clock_Frequency = crystal frequency of 9.8304MHz
Clock_Mode = value programmed in WR4
Baud_Rate = desired baud rate
Table 12 Time constants for common baud rates
(for 9.8304 MHz Clock)
3FFEH
300
1FFEH
600
0FFEH
1200
07FEH
2400
03FEH
4800
01FEH
9600
00FEH
19200
007EH38400
Baud Constant (Hex)Baud Rate
MPA-100 User's Manual 6-5