Motorola PowerQUICC II MPC8280 Series Reference Manual page 666

UART Baud Rate Examples
Table 17-3. Typical Baud Rates for Asynchronous Communication
Baud Rate
75
150
300
600
1200
2400
4800
9600
19,200
38,400
57,600
115,200
460,000
For synchronous communication, the internal clock is identical to the baud-rate output. To
get the preferred rate, select the system clock according to the following:
Sync Baud Rate
For example, to get a rate of 64 kbps, the system clock can be 24.96 MHz,
BRGCx[DIV16] = 0, and BRGCx[CD] = 389.
17-6
Freescale Semiconductor, Inc.
Using a 66-MHz BRG Input Clock
BRGCx[DIV16] BRGCx[CD]
1
1
1
1
0
0
0
0
0
0
0
0
0
BRGCLK or External Clock Source
= -------------------------------------------------------------------------------------------------- -
(
Prescale Divider
= ------------------------------------------------------------------------------------------------ -
(
BRGCx[DIV16]
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Actual Frequency (Hz)
3436 75.01
1718 149.98
858 300.13
429 599.56
3436 1200.2
1718 2399.7
858 4802.1
429 9593.0
214 19,186
106 38,551
71 57,292
35 114,583
8 458,333
) × (
Clock Divider + 1
BRGCx[EXTC]
) × (
BRGCx[CD] + 1
)
)
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