m37702s1afp Mitsumi Electronics, Corp., m37702s1afp Datasheet - Page 38

• Manufacturer Part Number: m37702s1afp
• Description: Single-chip 16-bit Cmos Microcomputer
• Manufacturer: Mitsumi Electronics, Corp.

MITSUBISHI MICROCOMPUTERS
M37702M2AXXXFP, M37702M2BXXXFP
M37702S1AFP, M37702S1BFP
SINGLE-CHIP 16-BIT CMOS MICROCOMPUTER
INPUT/OUTPUT PINS
Ports P8 to P0 all have a data direction register and each bit can
be programmed for input or output. A pin becomes an output pin
when the corresponding data direction register is set and an input
pin when it is cleared.
When pin programmed for output, the data is written to the port
latch and it is output to the output pin. When a pin is programmed
for output, the contents of the port latch is read instead of the
value of the pin. Therefore, a previously output value can be read
correctly even when the output “L” voltage is raised due to rea-
sons such as directly driving an LED.
A pin programmed for input is floating and the value input to the
pin can be read. When a pin is programmed for input, the data is
written only in the port latch and the pin stays floating.
If an input/output pin is not used as an output port, clear the bit of
the corresponding data direction register so that the pin become
input mode.
Figure 50 shows a block diagram of ports P8 to P0 in single-chip
_
mode and the E pin output.
In memory expansion mode, microprocessor mode, and evalua-
tion chip mode, ports P4 to P0 are also used as address, data,
and control signal pins.
Refer to the section on processor modes for more details.
38