M16C30P_07 Datasheet, PDF (150/317 Pages) Renesas Technology Corp – 16-BIT SINGLE-CHIP MICROCOMPUTER M16C FAMILY / M16C/30 SERIES

M16C/30P Group
15. Serial Interface
15.1.1.1 Counter Measure for Communication Error Occurs
If a communication error occurs while transmitting or receiving in clock synchronous serial I/O mode, follow
the procedures below.
• Resetting the UiRB register (i=0 to 2)
(1) Set the RE bit in the UiC1 register to “0” (reception disabled)
(2) Set the SMD2 to SMD0 bits in the UiMR register to “000b” (Serial interface disabled)
(3) Set the SMD2 to SMD0 bits in the UiMR register to “001b” (Clock synchronous serial I/O mode)
(4) Set the RE bit in the UiC1 register to “1” (reception enabled)
• Resetting the UiTB register (i=0 to 2)
(1) Set the SMD2 to SMD0 bits in the UiMR register “000b” (Serial interface disabled)
(2) Set the SMD2 to SMD0 bits in the UiMR register “001b” (Clock synchronous serial I/O mode)
(3) “1” is written to RE bit in the UiC1 register (transmission enabled), regardless of the TE bit in the UiCi
register
15.1.1.2 CLK Polarity Select Function
Use the CKPOL bit in the UiC0 register (i = 0 to 2) to select the transfer clock polarity. Figure 15.13 shows the
Transfer Clock Polarity.
(1) When the CKPOL bit in the UiC0 register = 0 (transmit data output at the falling
edge and the receive data taken in at the rising edge of the transfer clock)
CLKi
TXDi
D0 D1 D2 D3 D4 D5 D6 D7
(NOTE 2)
RXDi
D0 D1 D2 D3 D4 D5 D6 D7
(2) When the CKPOL bit = 1 (transmit data output at the rising edge and the receive
data taken in at the falling edge of the transfer clock)
CLKi
(NOTE 3)
TXDi
D0 D1 D2 D3 D4 D5 D6 D7
RXDi
D0 D1 D2 D3 D4 D5 D6 D7
NOTES:
1. This applies to the case where the UFORM bit in the UiC0 register = 0
(LSB first) and the UiLCH bit in the UiC1 register = 0 (no reverse).
2. When not transferring, the CLKi pin outputs a high signal.
3. When not transferring, the CLKi pin outputs a low signal.
i = 0 to 2
Figure 15.13 Transfer Clock Polarity
Rev.1.22 Mar 29, 2007 Page 134 of 291
REJ09B0179-0122