M38062M3-156FP MITSUBISHI [Mitsubishi Electric Semiconductor], M38062M3-156FP Datasheet - Page 20

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

Asynchronous serial I/O (UART) mode
Clock asynchronous serial I/O mode (UART) can be selected by
clearing the serial I/O mode selection bit of the serial I/O control
register to “0”.
Eight serial data transfer formats can be selected, and the transfer
formats used by a transmitter and receiver must be identical.
The transmit and receive shift registers each have a buffer, but the
Fig. 12 Block diagram of UART serial I/O
20
P4
P4
P4
6
/S
4
5
f(X
/R
/T
CLK1
X
X
IN
D
D
)
STdetector
BRG count source selection bit
1/4
Character length selection bit
Character length selection bit
7 bits
8 bits
Serial I/O1 synchronous clock selection bit
OE
Address 0018
PE FE
Receive shift register
Frequency division ratio 1/(n+1)
ST/SP/PA generator
Receive buffer
Data bus
Data bus
16
Baud rate generator
Transmit shift register
SP detector
Address 001C
Transmit buffer
Address
Serial I/O1 control register
two buffers have the same address in memory. Since the shift reg-
ister cannot be written to or read from directly, transmit data is
written to the transmit buffer, and receive data is read from the re-
ceive buffer.
The transmit buffer can also hold the next data to be transmitted,
and the receive buffer can hold a character while the next charac-
ter is being received.
1/16
16
Clock control circuit
0018
SINGLE-CHIP 8-BIT CMOS MICROCOMPUTER
16
Receive buffer full flag (RBF)
Receive interrupt request (RI)
Transmit interrupt source selection bit
Serial I/O1 status register
MITSUBISHI MICROCOMPUTERS
Address 001A
1/16
Transmit buffer empty flag (TBE)
Transmit shift completion flag (TSC)
UART control register
Transmit interrupt request (TI)
16
Address
Address 001B
3806 Group
0019
16
16