248
•
Mode 4
When the corresponding bit of A23E to A16E is set to 1, setting a PADDR bit to 1 makes the
corresponding port A pin an address output, while clearing the bit to 0 makes the pin an input
port. Clearing one of bits A23E to A16 to 0 makes the corresponding port A pin an I/O port,
and its function can be switched with PADDR.
•
Mode 7 (when bit EXPE is set to 1 in SYSCR)
When the corresponding bit of A23E to A16E is set to 1, setting a PADDR bit to 1 makes the
corresponding port A pin an address output, while clearing the bit to 0 makes the pin an input
port. Clearing one of bits A23E to A16E to 0 makes the corresponding port A pin an I/O port;
setting the corresponding PADDR bit to 1 makes the pin an output port, while clearing the bit
to 0 makes the pin an input port.
•
Mode 7 (when bit EXPE is cleared to 0 in SYSCR)
Port A is an I/O port, and its pin functions can be switched with PADDR.
Port A Data Register (PADR)
Bit
7
6
5
4
3
2
1
0
PA7DR
PA6DR
PA5DR
PA4DR
PA3DR
PA2DR
PA1DR
PA0DR
Initial value
0
0
0
0
0
0
0
0
Read/Write
R/W
R/W
R/W
R/W
R/W
R/W
R/W
R/W
PADR is an 8-bit readable/writable register that stores output data for the port A pins (PA7 to
PA0).
PADR is initialized to H'00 by a reset and in hardware standby mode. It retains its prior state in
software standby mode.
Port A Register (PORTA)
Bit
7
6
5
4
3
2
1
0
PA7
PA6
PA5
PA4
PA3
PA2
PA1
PA0
Initial value
—
*
—
*
—
*
—
*
—
*
—
*
—
*
—
*
Read/Write
R
R
R
R
R
R
R
R
Note:
*
Determined by the state of pins PA7 to PA0.
PORTA is an 8-bit read-only register that shows the pin states. PORTA cannot be written to;
writing of output data for the port A pins (PA7 to PA0) must always be performed on PADR.
If a port A read is performed while PADDR bits are set to 1, the PADR values are read. If a port A
read is performed while PADDR bits are cleared to 0, the pin states are read.
Содержание H8S/2670
Страница 5: ......
Страница 9: ......
Страница 199: ...182 ...
Страница 361: ...344 ...
Страница 393: ...376 ...
Страница 647: ...630 ...