HD643303x Hitachi, HD643303x Datasheet - Page 167

• Manufacturer Part Number: HD643303x
• Description: Hitachi Microcomputer
• Manufacturer: Hitachi

Bits 7 to 5, 3 and 1 are reserved. Bits 7 and 6 cannot be modified and always read 1. Bits 5, 3, and 1
can be written and read, but they cannot be used for port input or output. If bit 5, 3, or 1 in P9DDR
is read while its value is 1, the corresponding bit in P9DR is read directly. If bit 5, 3, or 1 in P9DDR
is read while its value is 0, it always reads 1.
P9DR is initialized to H'C0 by a reset and in hardware standby mode. In software standby mode it
retains its previous setting.
7.9.3 Pin Functions
The port 9 pins are also used for SCI input and output (TxD, RxD, SCK), and for IRQ
7-14 describes the selection of pin functions.
Table 7-14 Port 9 Pin Functions
Pin
P9
P9
P9
4
2
0
/SCK/IRQ
/RxD
/TxD
4
Pin Functions and Selection Method
Bit C/A in SMR of SCI, bits CKE0 and CKE1 in SCR of SCI, and bit P9
select the pin function as follows
Bit RE in SCR of SCI and bit P9
Bit TE in SCR of SCI and bit P9
CKE1
C/A
CKE0
P9
Pin function
RE
P9
Pin function
TE
P9
Pin function
4
2
0
DDR
DDR
DDR
input output
P9
P9
P9
0
4
2
0
0
0
0
input
input
P9
1
152
4
0
2
0
0
0
DDR select the pin function as follows
DDR select the pin function as follows
SCK output
P9
P9
2
0
—
output
output
0
1
1
1
IRQ
4
input
SCK output
—
—
1
TxD output
RxD input
—
—
1
1
SCK input
4
input. Table
—
—
—
1
4
DDR