M30201_M Datasheet, PDF (88/415 Pages) Renesas Technology Corp – 16-BIT SINGLE-CHIP MICROCOMPUTER M16C FAMILY

Serial I/O
Mitsubishi microcomputers
M30201 Group
SINGLE-CHIP 16-BIT CMOS MICROCOMPUTER
Serial I/O
Serial I/O is configured as two channels: UART0 and UART1.
UART0 and UART1 each have an exclusive timer to generate a transfer clock, so they operate indepen-
dently of each other.
Figure 1.69 shows the block diagram of UART0 and UART1. Figure 1.70 shows the block diagram of the
transmit/receive unit.
UART0 has two operation modes: a clock synchronous serial I/O mode and a clock asynchronous serial I/
O mode (UART mode). The contents of the serial I/O mode select bits (bits 0 to 2 at addresses 03A016 and
03A816) determine whether UART0 is used as a clock synchronous serial I/O or as a UART.
UART1 is used as a UART only.
Figures 1.71 through 1.73 show the registers related to UARTi.
(UART0)
RxD0
Clock source selection
f1
Bit rate generator
Internal
f8
f32
1 / (m+1)
fC
External
UART reception
1/16
Clock synchronous type
Reception
control circuit
UART transmission
1/16
Clock synchronous type
Transmission
control circuit
Clock synchronous type
(when internal clock is selected)
1/2
CLK0
CLKS
Clock synchronous type
(when internal clock is selected)
CLK
polarity
reversing
circuit
Clock output pin
select switch
Clock synchronous type
(when external clock is
selected)
Receive
clock
Transmit
clock
Transmit/
receive
unit
TxD0
(UART1)
RxD1
Clock source selection
f1
Bit rate generator ^1/16
f8
1 / (n+1)
f32
fC
1/16
m : Values set to UART0 bit rate generator (BRG0)
n : Values set to UART1 bit rate generator (BRG1)
Figure 1.69. Block diagram of UARTi (i = 0, 1)
Reception
control circuit
Transmission
control circuit
Receive
clock
Transmit
clock
Transmit/
receive
unit
TxD1
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