CHAPTER 4 PORT FUNCTIONS
Preliminary User’s Manual U19014EJ1V0UD
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4.2.2 Port 1
Port 1 is an 8-bit I/O port with an output latch. Port 1 can be set to the input mode or output mode in 1-bit units
using port mode register 1 (PM1). When the P10 to P17 pins are used as an input port, use of an on-chip pull-up
resistor can be specified in 1-bit units by pull-up resistor option register 1 (PU1).
This port can also be used for serial interface data I/O, clock I/O, and timer I/O.
Reset signal generation sets port 1 to input mode.
Figures 4-4 to 4-9 show block diagrams of port 1.
Caution To use P10/SCK10 and P12/SO10 as general-purpose ports, set serial operation mode register 10
(CSIM10) and serial clock selection register 10 (CSIC10) to the default status (00H).
Figure 4-4. Block Diagram of P10
P10/SCK10
WR
PU
RD
WR
PORT
WR
PM
PU10
Alternate
function
Output latch
(P10)
PM10
Alternate
function
EV
DD
P-ch
Selector
Internal bus
PU1
PM1
P1
P1:
Port register 1
PU1:
Pull-up resistor option register 1
PM1:
Port mode register 1
RD: Read
signal
WR
××
: Write
signal
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