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Section 8 I/O Ports
8.1
Overview
The H8/3827R Series is provided with six 8-bit I/O ports, one 4-bit I/O port, one 3-bit I/O port,
one 8-bit input-only port, and one 1-bit input-only port. Table 8.1 indicates the functions of each
port.
Each port has of a port control register (PCR) that controls input and output, and a port data
register (PDR) for storing output data. Input or output can be assigned to individual bits.
See 2.9.2, Notes on Bit Manipulation, for information on executing bit-manipulation instructions
to write data in PCR or PDR.
Ports 5, 6, 7, 8, and A are also used as liquid crystal display segment and common pins, selectable
in 8-bit units.
Block diagrams of each port are given in Appendix C, I/O Port Block Diagrams.
Table 8.1
Port Functions
Port
Description
Pins
Other Functions
Function
Switching
Registers
Port 1
•
8-bit I/O port
•
MOS input pull-up
option
P1
7
to P1
5
/
IRQ
3
to
IRQ
1
/
TMIF, TMIC
External interrupts 3 to 1
Timer event interrupts
TMIF, TMIC
PMR1
TCRF,
TMC
P1
4
/
IRQ
4
/
ADTRG
External interrupt 4 and A/D
converter external trigger
PMR1, AMR
P1
3
/TMIG
Timer G input capture input
PMR1
P1
2
, P1
1
/
TMOFH, TMOFL
Timer F output compare
output
PMR1
P1
0
/TMOW
Timer A clock output
PMR1
Port 3
•
8-bit I/O port
•
MOS input pull-up
option
•
Large-current port
P3
7
/AEVL
P3
6
/AEVH
P3
5
/TXD
31
P3
4
/RXD
31
P3
3
/SCK
31
SCI3-1 data output (TXD
31
),
data input (RXD
31
), clock
input/output (SCK
31
), and
asynchronous counter event
inputs AEVL, AEVH
PMR3
SCR31
SMR31
P3
2
/
RESO
P3
1
/UD
P3
0
/PWM
Reset output, timer C count-
up/down select input, and 14-
bit PWM output
PMR3