M16C30P_07 Datasheet, PDF (151/317 Pages) Renesas Technology Corp – 16-BIT SINGLE-CHIP MICROCOMPUTER M16C FAMILY / M16C/30 SERIES

M16C/30P Group
15. Serial Interface
15.1.1.3 LSB First/MSB First Select Function
Use the UFORM bit in the UiC0 register (i = 0 to 2) to select the transfer format. Figure 15.14 shows the
Transfer Format.
(1) When the UFORM bit in the UiC0 register = 0 (LSB first)
CLKi
TXDi
RXDi
D0 D1 D2 D3 D4 D5 D6 D7
D0 D1 D2 D3 D4 D5 D6 D7
(2) When the UFORM bit = 1 (MSB first)
CLKi
TXDi
D7 D6 D5 D4 D3 D2 D1 D0
RXDi
D7 D6 D5 D4 D3 D2 D1 D0
NOTES:
1. This applies to the case where 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) and the UiLCH bit in the UiC1
register = 0 (no reverse).
i = 0 to 2
Figure 15.14 Transfer Format
15.1.1.4 Continuous Receive Mode
In continuous receive mode, receive operation becomes enable when the receive buffer register is read. It is not
necessary to write dummy data into the transmit buffer register to enable receive operation in this mode.
However, a dummy read of the receive buffer register is required when starting the operation mode.
When the UiRRM bit (i = 0 to 2) = 1 (continuous receive mode), the TI bit in the UiC1 register is set to “0”
(data present in the UiTB register) by reading the UiRB register. In this case, i.e., UiRRM bit = 1, do not write
dummy data to the UiTB register in a program. The U0RRM and U1RRM bits are the bit 2 and bit 3 in the
UCON register, respectively, and the U2RRM bit is the bit 5 in the U2C1 register.
Rev.1.22 Mar 29, 2007 Page 135 of 291
REJ09B0179-0122