(7) Port P45
P45/TXD P-channel output disable bit
Serial I/O1 enable bit
Transmit enable bit
Direction register
TXD pull-up
Data bus
Port latch
Serial I/O1 output
(9) Port P47
Serial I/O1 mode selection bit
Serial I/O1 enable bit
SRDY1 output enable bit
Direction register
Data bus
Port latch
Serial I/O1 ready output
MITSUBISHI MICROCOMPUTERS
3874 Group
SINGLE-CHIP 8-BIT CMOS MICROCOMPUTER
(8) Port P46
Serial I/O1 synchronous
clock selection bit
Serial I/O1 enable bit
Serial I/O1 mode selection bit
Serial I/O1 enable bit
Direction register
SCLK1 pull-up
Data bus
Port latch
Serial I/O1 clock output
Serial I/O1 clock input
(10) Port P50
Direction register
Data bus
Port latch
TOUT output control bit
Timer output
(11) Port P54
Direction register
Data bus
Port latch
Pulse output mode
Timer output
CNTR0 interrupt input
Event count input
Pulse width measurement gate input
Fig. 13 Port block diagram (2)
18
(12) Port P55
Direction register
Data bus
Port latch
CNTR1 interrupt input
Event count input
Reload input