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6.2.2 Port 1
Port 1 is an 8-bit input/output port with output latch. P10 to P17 pins can be set to the input mode/output mode
bit-wise with a port mode register 1 (PM1). When P10 to P17 pins are used as input ports, an on-chip pull-up resistor
can be connected to them in 8-bit units with a pull-up resistor option register (PUO).
Alternate functions include an A/D converter analog input.
RESET input sets port 1 to input mode.
Figure 6-5 shows a block diagram of port 1.
Caution
On-chip pull-up resistor cannot be used for pins used as A/D converter analog input.
WR
PUO
RD
WR
PORT
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WR
PUO : Pull-up resistor option register
PM
RD
WR : Port 1 write signal
136
CHAPTER 6 PORT FUNCTIONS
Figure 6-5. P10 to P17 Block Diagrams
PUO1
Output Latch
(P10 to P17)
PM
PM10 to PM17
: Port mode register
: Port 1 read signal
Selector
V
DD
P-ch
P10/ANI0 to
P17/ANI7
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