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CHAPTER 14 SERIAL INTERFACE UART6
User’s Manual U19780EJ2V0UD
395
Figure 14-24. Configuration of Baud Rate Generator
Selector
POWER6
8-bit counter
Match detector
Baud rate
Baud rate generator
BRGC6: MDL67 to MDL60
1/2
POWER6, TXE6 (or RXE6)
CKSR6: TPS63 to TPS60
f
PRS
f
PRS
/2
f
PRS
/2
2
f
PRS
/2
3
f
PRS
/2
4
f
PRS
/2
5
f
PRS
/2
6
f
PRS
/2
7
f
PRS
/2
8
f
PRS
/2
9
f
PRS
/2
10
8-bit timer/
event counter
50 output
f
XCLK6
Remark
POWER6: Bit 7 of asynchronous serial interface operation mode register 6 (ASIM6)
TXE6:
Bit 6 of ASIM6
RXE6:
Bit 5 of ASIM6
CKSR6:
Clock selection register 6
BRGC6:
Baud rate generator control register 6
(2) Generation of serial clock
A serial clock to be generated can be specified by using clock selection register 6 (CKSR6) and baud rate
generator control register 6 (BRGC6).
The clock to be input to the 8-bit counter can be set by bits 3 to 0 (TPS63 to TPS60) of CKSR6 and the division
value (f
XCLK6
/4 to f
XCLK6
/255) of the 8-bit counter can be set by bits 7 to 0 (MDL67 to MDL60) of BRGC6.
14.4.4 Calculation of baud rate
(1) Baud rate calculation expression
The baud rate can be calculated by the following expression.
•
Baud rate = [bps]
f
XCLK6
: Frequency of base clock selected by TPS63 to TPS60 bits of CKSR6 register
k:
Value set by MDL67 to MDL60 bits of BRGC6 register (k = 4, 5, 6, ..., 255)
f
XCLK6
2
×
k