EM78P157N
8-Bit Microcontroller with OTP ROM
3.2.3 EM78P157NAAS Pin Descriptions
Symbol Pin No. Type
VDD
15
–
OSCI
17
I
OSCO
16
I/O
TCC
4
I
/RESET
5
I
P50~P53
18, 19,
2, 3
I/O
P60~P67 7~14
I/O
/INT
7
I
VSS
6
–
Function
y Power supply
y XTAL type: Crystal input terminal or external clock input pin
y ERC type: RC oscillator input pin
y XTAL type: Output terminal for crystal oscillator or external clock input pin
y RC type: Instruction clock output
y External clock signal input
y The real time clock/counter (with Schmitt trigger input pin), must be tied to
VDD or VSS if not in use
y Input pin with Schmitt trigger. If this pin remains at logic low, the controller
will also remain at reset condition.
y P50~P53 are bi-directional I/O pins
y P50 and P51 can also be defined as the R-option pins
y P50~P52 can be set as pull-down by software
y P60~P67 are bi-directional I/O pins
y These pins can be set as pull-high or open-drain through software
programming
y P60~P63 can also be set as pull-down by software
y External interrupt pin triggered by falling edge
y Ground
3.2.4 EM78P157NAKM Pin Descriptions
Symbol Pin No. Type
VDD
15,16
–
OSCI
18
I
OSCO
17
I/O
TCC
3
I
/RESET
4
I
P50~P53 19, 20, 1, 2 I/O
P60~P67 7~14
I/O
/INT
7
I
VSS
5, 6
–
Function
y Power supply
y XTAL type: Crystal input terminal or external clock input pin
y ERC type: RC oscillator input pin
y XTAL type: Output terminal for crystal oscillator or external clock input pin
y RC type: Instruction clock output
y External clock signal input
y The real time clock/counter (with Schmitt trigger input pin), must be tied to
VDD or VSS if not in use
y Input pin with Schmitt trigger. If this pin remains at logic low, the controller
will also remain at reset condition.
y P50~P53 are bi-directional I/O pins
y P50 and P51 can also be defined as the R-option pins
y P50~P52 can be set as pull-down by software
y P60~P67 are bi-directional I/O pins
y These pins can be set as pull-high or open-drain through software
programming
y P60~P63 can also be set as pull-down by software
y External interrupt pin triggered by falling edge
y Ground
4•
Product Specification (V1.0) 09.22.2005
(This specification is subject to change without further notice)