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CHAPTER 4 PORT FUNCTIONS
User’s Manual U15104EJ2V0UD
4.2 Port Configuration
The ports consist of the following hardware.
Table 4-2. Port Configuration
Item
Configuration
Control register
Port mode register (PMm: m = 0, 3 to 7, 12)
Port
Total: 62 port pins (6 inputs, 3 outputs, 53 I/Os)
4.2.1 Port 0
Port 0 is a 7-bit I/O port with an output latch. Input or output mode can be specified for port 0 in 1-bit units using
port mode register 0 (PM0).
Alternate functions include external interrupt request input.
Reset input sets port 0 to the input mode.
Figures 4-2 and 4-3 show the block diagrams of port 0.
Caution Because port 0 also serves as an external interrupt request input, when the port function output
mode is specified and the output level is changed, the interrupt request flag is set. Thus, when
the output mode is used, set the interrupt mask flag to 1.
Figure 4-2. Block Diagram of P00 to P04
PM:
Port mode register
RD:
Port 0 read signal
WR: Port 0 write signal
P00/INTP0
P01/INTP1
P02/INTP2
P03/INTP3
P04/INTP4
RD
WR
PORT
WR
PM
Alternate function
Output latch
(P00 to P04)
PM00 to PM04
Internal bus
Selector