Datasheet

Section 8 I/O Ports
Rev. 4.00 Jun 06, 2006 page 190 of 1004
REJ09B0301-0400
Table 8.1 H8S/2138 Group Port Functions
Expanded Modes Single-Chip Mode
Port
Description
Pins
Mode 1
Mode 2, Mode 3
(EXPE = 1)
Mode 2, Mode 3
(EXPE = 0)
Port 1 • 8-bit I/O port
•On-chip
MOS input
pull-ups
•LED drive
capability
P17 to P10/
A7 to A0/
PW7 to PW0
Lower address
output
(A7 to A0)
When DDR = 0
(after reset): input
port
When DDR = 1:
lower address
output (A7 to A0) or
PWM timer output
(PW7 to PW0)
I/O port also functioning
as PWM timer output
(PW7 to PW0)
Port 2 • 8-bit I/O port
•On-chip
MOS input
pull-ups
•LED drive
capability
P27/A15/PW15/
CBLANK
P26/A14/PW14
P25/A13/PW13
P24/A12/PW12
P23/A11/PW11
P22/A10/PW10
P21/A9/PW9
P20/A8/PW8
Upper address
output
(A15 to A8)
When DDR = 0
(after reset): input
port or timer
connection output
(CBLANK)
When DDR = 1:
upper address
output (A15 to A8),
PWM timer output
(PW15 to PW12),
timer connection
output (CBLANK),
or output ports (P27
to P24)
I/O port also functioning
as PWM timer output
(PW15 to PW8) and timer
connection output
(CBLANK)
Port 3 • 8-bit I/O port
•On-chip
MOS input
pull-ups
•LED drive
capability
P37 to P30/
HDB7 to HDB0/
D7 to D0
Data bus input/output (D7 to D0) I/O port also functioning
as host interface data bus
input/output (HDB7 to
HDB0)