14. Serial I/O
puorG92/C61M
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854fo7002,03.raM21.1.veR
2110-1010B90JER
14.2 SI/O3 and SI/O4
Note
The SI/O4 interrupt of peripheral function interrupt is not available in the 64-pin package.
SI/O3 and SI/O4 are exclusive clock-synchronous serial I/Os.
Figure 14.35 shows the block diagram of SI/O3 and SI/O4, and Figure 14.36 shows the SI/O3 and SI/O4-
related registers.
Table 14.20 shows the specifications of SI/O3 and SI/O4.
Figure 14.35 SI/O3 and SI/O4 Block Diagram
Data bus
SI/Oi
interrupt request
Note: i = 3, 4.
n = A value set in the SiBRG register.
SiTRR register
SI/O counter i
8
SMi5 LSB MSB
SMi2
SMi3
SMi3
SMi6
SMi1 to SMi0
CLK
i
S
OUTi
S
INi
SiBRG register
SMi6
1/(n+1)
1/2
1/2
Main clock,
PLL clock,
or on-chip oscillator
clock
f
1SIO
1/2
1/8
1/4
f
8SIO
f
32SIO
f
2SIO
PCLK1=0
PCLK1=1
SMi4
00
2
01
2
10
2
Clock source select
Synchronous
circuit
CLK
polarity
reversing
circuit