Serial I/O (Clock Synchronous Serial I/O)
153
Mitsubishi microcomputers
M16C / 62P Group
SINGLE-CHIP 16-BIT CMOS MICROCOMPUTER
development
Preliminary Specifications Rev.1.0
Specifications in this manual are tentative and subject to change.
(c) Continuous Receive Mode
When the UiRRM bit (i = 0 to 2) = 1 (continuous receive mode), the UiC1 register’s TI bit is set to “1”
(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 UCON
register bit 2 and bit 3, respectively, and the U2RRM bit is the U2C1 register bit 4.
(d) Serial Data Logic Switching Function
When the UiC1 register (i = 0 to 2)’s UiLCH bit = 1 (reverse), 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 1.18.4 shows serial data logic.
Figure
1.18.4.
Serial Data Logic Switching
D0
D1
D2
D3
D4
D5
D6
D7
Transfer clock
TxD
i
(no reverse)
“H”
“L”
“H”
“L”
TxD
i
(reverse)
D0
D1
D2
D3
D4
D5
D6
D7
“H”
“L”
(1) When the UiC1 register's UiLCH bit = 0 (no reverse)
Transfer clock
“H”
“L”
(2) When the UiC1 register's UiLCH bit = 1 (reverse)
Note: This applies to the case where the UiC0 register’s CKPOL bit = 0
(transmit data output at the falling edge and the receive data
taken in at the rising edge of the transfer clock) and the UFORM
bit = 0 (LSB first).
i = 0 to 2
(e) Transfer Clock Output From Multiple Pins (UART1)
Use the UCON register’s CLKMD1 to CLKMD0 bits to select one of the two transfer clock output pins.
(See Figure 1.18.5.) This function can be used when the selected transfer clock for UART1 is an
internal clock.
Figure 1.18.5. Transfer Clock Output From Multiple Pins
Microcomputer
T
X
D
1
(P6
7
)
CLKS
1
(P6
4
)
CLK
1
(P6
5
)
IN
CLK
IN
CLK
Note: This applies to the case where the U1MRregister's CKDIR bit
= 0 (internal clock) and the UCON register's CLKMD1 bit = 1 (
transfer clock output from multiple pins).
Transfer enabled
when the UCON
register's
CLKMD0 bit = 0
Transfer enabled
when the UCON
register's
CLKMD0 bit = 1