M38867E8AHP MITSUBISHI [Mitsubishi Electric Semiconductor], M38867E8AHP Datasheet - Page 12

• Manufacturer Part Number: M38867E8AHP
• Description: SINGLE-CHIP 8-BIT CMOS MICROCOMPUTER??
• Manufacturer: MITSUBISHI [Mitsubishi Electric Semiconductor]

I/O PORTS
The I/O ports have direction registers which determine the input/
output direction of each individual pin. Each bit in a direction reg-
ister corresponds to one pin, and each pin can be set to be input
port or output port.
When “0” is written to the bit corresponding to a pin, that pin be-
comes an input pin. When “1” is written to that bit, that pin
becomes an output pin.
If data is read from a pin which is set to output, the value of the
port output latch is read, not the value of the pin itself. Pins set to
input are floating. If a pin set to input is written to, only the port
Table 4 I/O port function (1)
12
P4
P4
P0
P1
P4
OBF
P4
OBF
P4
/OBF
P4
/S
P0
P2
P3
P3
P3
P4
P4
1
1
0
1
2
3
0
0
0
0
1
2
4
5
6
7
–P0
/X
/X
/INT
/INT
/P3
–P1
–P2
/PWM
/PWM
–P3
/R
/T
/S
/S
00
01
Pin
10
COUT
CIN
CLK1
RDY1
X
X
D
REF
D
7
7
7
7
0
1
/
/
00
10
Port P2
Port P0
Port P1
Port P3
Port P4
Name
Input/output,
individual bits
Input/Output
CMOS compatible
input level
CMOS 3-state output
or N-channel open-
drain output
CMOS compatible
input level
CMOS 3-state output
CMOS compatible
input level
CMOS 3-state output
(when selecting bus
interface function)
CMOS compatible
input level or TTL
input level
CMOS compatible
input level or TTL
input level
CMOS 3-state output
or N-channel open-
drain output
I/O Structure
output latch is written to and the pin remains floating.
When the P8 function select bit of the port control register 2 (ad-
dress 002F
the port P4 input register, and read from address 0011
the port P7 input register.
As the particular function, value of P4
pins can be read regardless of setting direction registers, by read-
ing the port P4 input register (address 0010
register (address 0011
A d d r e s s h i g h - o r d e r
byte output
Serial I/O1 function out-
put
Bus interface function
input
Address low-order byte
output
Data bus I/O
Control signal I/O
PWM output
Key-on wake up input
Comparator input
Control signal I/O
Key-on wake up input
Comparator input
Sub-clock generating
circuit
External interrupt input
Bus interface function
I/O
Serial I/O1 function in-
put
Serial I/O1 function out-
put
Serial I/O1 function I/O
Bus interface function
output
Address low-order byte
output
A n a l o g c o m p a r a t o r
power source input pin
Non-Port Function
SINGLE-CHIP 8-BIT CMOS MICROCOMPUTER
16
) is set to “1”, read from address 0010
MITSUBISHI MICROCOMPUTERS
16
) respectively.
CPU mode register
Port control register 1
CPU mode register
CPU mode register
Port control register 1
AD/DA control register
CPU mode register
Port control register 1
CPU mode register
Interrupt edge selection
register
Port control register 2
Serial I/O1 control
register
Port control register 2
Serial I/O1 control
register
Data bus buffer control
register
Port control register 2
Serial I/O1 control
register
Data bus buffer control
register
CPU mode register
Port control register 1
Serial I/O2 control
register
Serial I/O1 control
register
UART control register
Port control register 2
Related SFRs
2
to P4
3886 Group
16
6
) or the port P7 input
pins and P7
16
16
becomes
becomes
Ref.No.
0
(10)
(11)
(12)
(13)
(14)
(2)
(3)
(4)
(5)
(6)
(7)
(8)
(9)
(1)
to P7
5