CHAPTER 11 SERIAL INTERFACE FUNCTION
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User’s Manual U14359EJ4V0UM
11.2.6 Dedicated baud rate generators 0 to 2 (BRG0 to BRG2)
A dedicated baud rate generator, which consists of a source clock selector and an 8-bit programmable counter,
generates serial clocks during transmission/reception in UARTn. The dedicated baud rate generator output can be
selected as the serial clock for each channel.
Separate 8-bit counters exist for transmission and for reception.
(1) Baud rate generator configuration
Figure 11-12. Baud Rate Generator Configuration
f
XX
/2
f
XX
f
XX
/4
f
XX
/8
f
XX
/16
f
XX
/32
f
XX
/64
f
XX
/128
f
XX
/256
f
XX
/512
f
XX
/1,024
f
XX
/2,048
Clock
(f
XCLK
)
Selector
UARTCAEn
8-bit counter
Match detector
Baud rate
BRGCn: BRGn7 to BRGn0
1/2
UARTCAEn and TXEn (or RXEn)
CKSRn: TPSn3 to TPSn0
Remarks 1
. n = 0 to 2
2.
f
XX
: Internal system clock
(a) Basic clock (Clock)
When UARTCAEn = 1 in the ASIMn register, the clock selected according to the TPSn3 to TPSn0 bits of
the CKSRn register is supplied to the transmission/reception unit. This clock is called the basic clock,
and its frequency is referred to as f
XCLK
. When UARTCAEn = 0, the clock signal is fixed at low level.
