M38203M4 Datasheet, PDF (219/344 Pages) Mitsubishi Electric Semiconductor – 8-BIT SINGLE-CHIP MICROCOMPUTER

APPLICATION
2.5 Serial I/O1
(2) Clock asynchronous serial I/O (UART) mode
Figure 2.5.22 and Figure 2.5.23 show a transmitting method in the UART mode. Figure 2.5.24 and
Figure 2.5.25 show a receiving method in the UART mode.
[Notes on use]
Notes 1: When an external clock is selected in setting Ž below, BRG setting is not required in
setting  below.
2: In the full duplex data transfer mode, set the receive enable bit (bit 5) to “1” (receive
enabled) in setting Ž below.
3: To use a serial I/O1 transmit interrupt, set in the following sequence.
4: When no serial I/O1 transmit interrupt is used, omit setting Œ, , ‘ and “ below.
ŒDisable Serial I/O1 transmit interrupt
b7
b0
0
ICON1: Interrupt control register 1 [Address 3E16]
b3: Serial I/O1 transmit interrupt enable bit
0: Interrupts disabled
Set the value to baud rate generator (BRG) [Address 1C16]
ŽSetting of serial I/O1 control register
Selection of clock asynchronous mode, transmit, or others
b7
b0
10 1
SIO1CON: Serial I/O1 control register [Address 1A16]
b0: BRG count source selection bit
0: f(XIN)
1: f(XIN)/4
b1: Serial I/O1 synchronization clock selection bit
(In UART mode)
0: BRG output/16
1: External clock input/16
b2: SRDY1 output enable bit
Invalied in UART mode
b3: Transmit interrupt source selection bit
0: When transmit buffer has emptied
1: When transmit shift operation is completed
b4: Transmit enable bit
1: Transmit enabled
b5: Receive enable bit
0: Receive disabled
1: Receive enabled
b6: Serial I/O1 mode selection bit
0: Clock asynchronous serial I/O1 (UART) mode
b7: Serial I/O1 enable bit
1: Serial I/O1 enabled
(pins P44–P47 operate as serial I/O1 pins)
Continued to Figure 2.5.23
Fig. 2.5.22 Transmitting method in UART mode (1)
3820 GROUP USER’S MANUAL
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