M16C6KA_15 Datasheet, PDF (100/270 Pages) Renesas Technology Corp – SINGLE-CHIP 16-BIT CMOS MICROCOMPUTER Description

M16C/6KA Group
Clock synchronous serial I/O mode
(a) Polarity selection function
As shown in Fig.GA-10, the CLK polarity selection bit (bit 6 at address 03AC16) allows to select the polarity
of the transfer clock.
• When CLK polarity selection bit = “0”
CLK1
TXD1
D0 D1 D2 D3 D4 D5 D6 D7
RXD1
D0 D1 D2 D3 D4 D5 D6 D7
Note 1: The CLK pin level is "H" when
there is no transferring.
• When CLK polarity select bit = “1”
CLK1
TXD1
D0 D1 D2 D3 D4 D5 D6 D7
RXD1
D0 D1 D2 D3 D4 D5 D6 D7
Note 2: The CLK pin level is "L" when
there is no transferring.
Fig.GA-10 Polarity of transfer clock
(b) LSB first/MSB first selection function
As shown in Fig.GA-11, when the transfer format selection bit (bit 7 at address 03AC16) = “0”, the transfer
format is “LSB first”; when the bit = “1”, the transfer format is “MSB first”.
• When transfer format selection bit = “0”
CLK1
TXD1
D0 D1 D2 D3 D4 D5 D6 D7
RXD1
D0 D1 D2 D3 D4 D5 D6 D7
LSB first
• When transfer format selection bit = “1”
CLK1
TXD1
D7 D6 D5 D4 D3 D2 D1 D0
RXD1
D7 D6 D5 D4 D3 D2 D1 D0
MSB first
Fig.GA-11 Transfer format
Note: This applies when the CLK polarity selection bit = “0”.
Rev.1.00 Jul 16, 2004 page 98 of 266
REJ03B0100-0100Z