M38062M3-156FP MITSUBISHI [Mitsubishi Electric Semiconductor], M38062M3-156FP Datasheet - Page 19

• Manufacturer Part Number: M38062M3-156FP
• Description: SINGLE-CHIP 8-BIT CMOS MICROCOMPUTER
• Manufacturer: MITSUBISHI [Mitsubishi Electric Semiconductor]

Serial I/O1
Serial I/O1 can be used as either clock synchronous or asynchro-
nous (UART) serial I/O. A dedicated timer is also provided for
baud rate generation.
Fig. 10 Block diagram of clock synchronous serial I/O1
Fig. 11 Operation of clock synchronous serial I/O1 function
Write pulse to receive/transmit
buffer (address 0018
Receive enable signal S
Transfer shift clock
(1/2 to 1/2048 of the internal
clock, or an external clock)
P4
P4
Notes 1 : The transmit interrupt (TI) can be selected to occur either when the transmit buffer has emptied (TBE=1) or after the
P4
P4
7
6
/S
/S
4
f(X
5
/R
/T
X
RDY1
CLK1
IN
X
IN
X
Serial output TxD
2 : If data is written to the transmit buffer when TSC=0, the transmit clock is generated continuously and serial data is
3 : The receive interrupt (RI) is set when the receive buffer full flag (RBF) becomes “1” .
D
D
Serial input RxD
)
control register.
output continuously from the TxD pin.
transmit shift operation has ended (TSC=1), by setting the transmit interrupt source selection bit (TIC) of the serial I/O1
16
BRG count source selection bit
)
RDY1
F/F
TBE = 0
1/4
Falling-edge detector
TBE = 1
TSC = 0
Receive shift register
D
D
0
0
Receive buffer
Transmit shift register
Data bus
Data bus
Transmit buffer
D
D
1
1
Address 0018
Shift clock
Serial I/O1 synchronous
clock selection bit
Frequency division ratio 1/(n+1)
Baud rate generator
Address 0018
Shift clock
Address 001C
D
D
2
2
16
Clock synchronous serial I/O mode
Clock synchronous serial I/O1 mode can be selected by setting
the mode selection bit of the serial I/O1 control register to “1”.
For clock synchronous serial I/O1, the transmitter and the receiver
must use the same clock. If an internal clock is used, transfer is
started by a write signal to the TB/RB (address 0018
Clock control circuit
16
D
D
Clock control circuit
16
3
3
Serial I/O1 control register
SINGLE-CHIP 8-BIT CMOS MICROCOMPUTER
Transmit interrupt source selection bit
Receive buffer full flag (RBF)
Serial I/O1 status register
1/4
D
D
4
4
Receive interrupt request (RI)
D
D
5
5
Transmit buffer empty flag (TBE)
Transmit shift completion flag (TSC)
Transmit interrupt request (TI)
D
D
6
6
Address 001A
Address 0019
Overrun error (OE)
detection
3806 Group
RBF = 1
TSC = 1
D
D
7
7
16
16
16
).
19