Datasheet

Section 8 I/O Ports
Rev. 4.00 Jun 06, 2006 page 220 of 1004
REJ09B0301-0400
8.6.3 Pin Functions
Port 5 pins also function as SCI0 I/O pins (TxD0, RxD0, SCK0) and the IIC0 I/O pin (SCL0). The
port 5 pin functions are shown in table 8.12.
Table 8.12 Port 5 Pin Functions
Pin Selection Method and Pin Functions
P52/SCK0/SCL0 The pin function is switched as shown below according to the combination of
bits CKE1 and CKE0 in SCR of SCI0, bit C/A in SMR of SCI0, bit ICE in ICCR
of IIC0, and bit P52DDR.
ICE 0 1
CKE1 0 1 0
C/A 01— 0
CKE0 0 1 —— 0
P52DDR 0 1 ————
Pin function P52
input pin
P52
output pin
SCK0
output pin
SCK0
output pin
SCK0
input pin
SCL0
I/O pin
When this pin is used as the SCL0 I/O pin, bits CKE1 and CKE0 in SCR of
SCI0 and bit C/A in SMR of SCI0 must all be cleared to 0.
SCL0 is an NMOS open-drain output, and has direct bus drive capability.
In the H8S/2138 Group, when set as the P52 output pin or SCK0 output pin,
this pin is an NMOS push-pull output.
P51/RxD0 The pin function is switched as shown below according to the combination of
bit RE in SCR of SCI0 and bit P51DDR.
RE 0 1
P51DDR 0 1 —
Pin function P51 input pin P51 output pin RxD0 input pin
P50/TxD0 The pin function is switched as shown below according to the combination of
bit TE in SCR of SCI0 and bit P50DDR.
TE 0 1
P50DDR 0 1 —
Pin function P50 input pin P50 output pin TxD0 output pin