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CHAPTER 4 PORT FUNCTIONS
User’s Manual U15104EJ2V0UD
4.3 Registers Controlling Port Functions
The following two types of registers control the ports.
•
Port mode registers (PM0, PM3 to PM7, PM12)
•
Pull-up resistor option register (PU4)
(1) Port mode registers (PM0, PM3 to PM7, PM12)
These registers are used to set the port input/output mode in 1-bit units.
PM0, PM3 to PM7, and PM12 are independently set with a 1-bit or 8-bit memory manipulation instruction.
Reset input sets these registers to FFH.
When using a port pin as an alternate-function pin, set the values of the port mode registers and the output
latches as shown in Table 4-3.
Cautions 1.
P10 to P17 are input-only pins, and P130 to P132 are output-only pins.
2.
As port 0 has an alternate function as an external interrupt 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.
Содержание mPD178053
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