M16C30_02 Datasheet, PDF (109/178 Pages) Renesas Technology Corp – SINGLE-CHIP 16-BIT CMOS MICROCOMPUTER

Clock synchronous serial I/O mode
Mitsubishi microcomputers
M16C / 30 Group
SINGLE-CHIP 16-BIT CMOS MICROCOMPUTER
(a) Polarity select function
As shown in Figure 1.16.12, the CLK polarity select bit (bit 6 at addresses 03A416, 03AC16, 037C16)
allows selection of the polarity of the transfer clock.
• When CLK polarity select bit = “0”
CLKi
TXDi
D0 D1 D2 D3 D4 D5 D6 D7
RXDi
D0 D1 D2 D3 D4 D5 D6 D7
Note 1: The CLKi pin level when not
transferring data is “H”.
• When CLK polarity select bit = “1”
CLKi
TXDi
D0 D1 D2 D3 D4 D5 D6 D7
RXDi
D0 D1 D2 D3 D4 D5 D6 D7
Note 2: The CLKi pin level when not
transferring data is “L”.
Figure 1.16.12. Polarity of transfer clock
(b) LSB first/MSB first select function
As shown in Figure 1.16.13, when the transfer format select bit (bit 7 at addresses 03A416, 03AC16,
037C16) = “0”, the transfer format is “LSB first”; when the bit = “1”, the transfer format is “MSB first”.
• When transfer format select bit = “0”
CLKi
TXDi
D0 D1 D2 D3 D4 D5 D6 D7
RXDi
D0 D1 D2 D3 D4 D5 D6 D7
LSB first
• When transfer format select bit = “1”
CLKi
TXDi
RXDi
D7 D6 D5 D4 D3 D2 D1 D0
D7 D6 D5 D4 D3 D2 D1 D0
MSB first
Note: This applies when the CLK polarity select bit = “0”.
Figure 1.16.13. Transfer format
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