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CHAPTER 5 PORT FUNCTIONS
5.3 Port Function Control Registers
The following two types of registers control the ports.
• Port mode registers (PM0, PM2 to PM6, PM8, PM9)
• Pull-up resistor option register (PU0)
(1) Port mode registers (PM0, PM2 to PM6, PM8, PM9)
These registers are used to set port input/output in 1-bit units.
PM0, PM2 to PM6, PM8, and PM9 are independently set with a 1-bit or 8-bit memory manipulation instruction.
RESET input sets registers to FFH.
Cautions 1. Pins P10 and P14 are input-only pins, and pins P20 to P27 and P30 to P37 are output-
only pins.
2. Port 0 has an alternate function as external interrupt request input, when the port function
output mode is specified and the output level is changed, the interrupt request flag is
set. When the output mode is used, therefore, the interrupt mask flag should be set to
1 beforehand.
3. Ports 2 and 3 that can be also used as meter driving PWM signal output pins go into a
high-impedance state when 1 is set to PM2
×
and PM3
×
, respectively.
Summary of Contents for mPD780973 Series
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