M16C6S_09 Datasheet, PDF (115/208 Pages) Renesas Technology Corp – SINGLE-CHIP 16-BIT CMOS MICROCOMPUTER

M16C/6S Group
UART Mode
(b) Serial Data Logic Switching Function
The data written to the UiTB register has its logic reversed before being transmitted. Similarly, the
received data has its logic reversed when read from the UiRB register. Figure 1.15.4 shows serial data
logic.
(1) When the UiC1 register's UiLCH bit = 0 (no reverse)
Transfer clock ^{“H”}
“L”
TxDi “H”
(no reverse) _{“L”}
ST D0 D1 D2 D3 D4 D5 D6 D7 P SP
(2) When the UiC1 register's UiLCH bit = 1 (reverse)
Transfer clock ^{“H”}
“L”
TxDi ^{“H”}
(reverse) _{“L”}
ST D0 D1 D2 D3 D4 D5 D6 D7 P SP
Note: This applies to the case where the UiC0 register’s CKPOL bit = 0 (
transmit data output at the falling edge of the transfer clock), the
UiC0 register's UFORM bit = 0 (LSB first), the UiMR register's
STPS bit = 0 (1 stop bit) and UiMR register's PRYE bit = 1 (parity
enabled).
ST : Start bit
P : Parity bit
SP : Stop bit
i = 0 to 2
Figure 1.15.4. Serial Data Logic Switching
(c) TxD and RxD I/O Polarity Inverse Function
This function inverses the polarities of the TXDi pin output and RXDi pin input. The logic levels of all
input/output data (including the start, stop and parity bits) are inversed. Figure 1.15.5 shows the TXD
pin output and RXD pin input polarity inverse.
(1) When the UiMR register's IOPOL bit = 0 (no reverse)
Transfer clock ^{“H”}
“L”
TxDi “H”
(no reverse) “L”
ST D0 D1 D2 D3 D4 D5 D6 D7 P SP
RxDi ^{“H”}
(no reverse) “L”
ST D0 D1 D2 D3 D4 D5 D6 D7 P SP
(2) When the UiMR register's IOPOL bit = 1 (reverse)
Transfer clock ^{“H”}
“L”
TxDi “H”
(reverse) “L”
ST D0 D1 D2 D3 D4 D5 D6 D7 P
RxDi
(reverse)
“H”
“L”
ST D0 D1 D2 D3 D4 D5 D6 D7 P
Note: This applies to the case where the UiC0 register's UFORM bit = 0
(LSB first), the UiMR register's STPS bit = 0 (1 stop bit) and the
UiMR register's PRYE bit = 1 (parity enabled).
SP
SP
ST : Start bit
P : Parity bit
SP : Stop bit
i = 0 to 2
Figure 1.15.5. TXD and RXD I/O Polarity Inverse
Rev.5.01 Dec 10, 2009 page 115 of 201
REJ03B0014-0501