R01UH0092EJ0110 Rev.1.10
Page 526 of 807
Jul 31, 2012
M16C/64C Group
24. Serial Interface SI/O3 and SI/O4
24.3
Operations
24.3.1
Basic Operations
SI/Oi transmits and receives data simultaneously. The SiTRR register is not divided into a register for
transmission/reception and buffer. Write transmit data to the SiTRR register while transmission/
reception is stopped. Read receive data from the SiTRR register while transmission/reception is
stopped.
24.3.2
CLK Polarity Selection
Use the SMi4 bit in the SiC register to select the transmit/receive clock polarity. Figure 24.2 shows
Polarity of Transmit/Receive Clock.
Figure 24.2
Polarity of Transmit/Receive Clock
(2) When the SMi4 bit = 1
D1
D2
D3
D4
D5
D6
D7
D1
D2
D3
D4
D5
D6
D7
D0
D0
SOUTi
SINi
CLKi
(1) When the SMi4 bit in the SiC register = 0
D1
D2
D3
D4
D5
D6
D7
D0
D1
D2
D3
D4
D5
D6
D7
D0
SOUTi
SINi
CLKi
Notes:
The above diagram assumes the following:
1. The SMi5 bit in the SiC register is 0 (LSB first).
2. The SMi6 bit in the SiC register is 1 (internal clock).
3. The SM26 bit or SM27 bit in the S34C2 register is 1 (SOUTi output retains last bit level)
i = 3, 4
High level is output when not
transmitting/receiving data
Low level is output when not
transmitting/receiving data
Содержание M16C Series
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