CHAPTER 4 PORT FUNCTIONS
Preliminary User’s Manual U19014EJ1V0UD
62
4.2.1 Port 0
Port 0 is a 2-bit I/O port with an output latch. Port 0 can be set to the input mode or output mode in 1-bit units
using port mode register 0 (PM0). When the P00 and P01 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 0 (PU0).
This port can also be used for timer I/O.
Reset signal generation sets port 0 to input mode.
Figures 4-2 and 4-3 show block diagrams of port 0.
Figure 4-2. Block Diagram of P00
P00/TI000
WR
PU
RD
WR
PORT
WR
PM
PU00
Alternate function
Output latch
(P00)
PM00
EV
DD
P-ch
Selector
Internal bus
PU0
PM0
P0
P0:
Port register 0
PU0:
Pull-up resistor option register 0
PM0:
Port mode register 0
RD: Read
signal
WR
××
: Write
signal
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