EM78P157N
8-Bit Microcontroller with OTP ROM
3.2 Pin Descriptions
3.2.1 EM78P157NBP and EM78P157NBM Pin Descriptions
Symbol Pin No. Type
Function
VDD
10
–
Power supply
y
y
y
XTAL type: Crystal input terminal or external clock input pin
ERC type: RC oscillator input pin
OSCI
12
I
XTAL type: Output terminal for crystal oscillator or external clock input pin
RC type: Instruction clock output
External clock signal input
y
y
y
OSCO
11
I/O
The real time clock/counter (with Schmitt trigger input pin), must be tied
to VDD or VSS if not in use
y
TCC
3
4
I
I
Input pin with Schmitt trigger. If this pin remains at logic low, the controller
will also remain at reset condition.
y
/RESET
P50~P53 are bi-directional I/O pins
P50 and P51 can also be defined as the R-option pins
P50~P52 can be set as pull-down by software
y
y
y
13, 14,
1, 2
P50~P53
I/O
P60~P61 are bi-directional I/O pins
These pins can be set as pull-high, pull-down, or open-drain through
software programming
y
y
P60~P61
P66~P67
6~7
8~9
I/O
I/O
P66~P67 are bi-directional I/O pins
These pins can be set as pull-high or open-drain through software
programming
y
y
/INT
VSS
6
5
I
External interrupt pin triggered by falling edge
Ground
y
y
–
3.2.2 EM78P157NAP and EM78P157NAM Pin Descriptions
Symbol Pin No. Type
Function
VDD
14
–
Power supply
y
y
y
XTAL type: Crystal input terminal or external clock input pin
ERC type: RC oscillator input pin
OSCI
16
I
XTAL type: Output terminal for crystal oscillator or external clock input pin
RC type: Instruction clock output
External clock signal input
y
y
y
OSCO
15
I/O
The real time clock/counter (with Schmitt trigger input pin), must be tied to
VDD or VSS if not in use
y
TCC
3
4
I
I
Input pin with Schmitt trigger. If this pin remains at logic low, the controller
will also remain at reset condition.
y
/RESET
P50~P53 are bi-directional I/O pins
P50 and P51 can also be defined as the R-option pins
P50~P52 can be set as pull-down by software
y
y
y
17,18,
1, 2
P50~P53
P60~P67
I/O
I/O
P60~P67 are bi-directional I/O pins
These pins can be set as pull-high or open-drain through software
programming
y
y
6~13
P60~P63 can also be set as pull-down by software
y
y
y
/INT
VSS
6
5
I
External interrupt pin triggered by falling edge
Ground
–
Product Specification (V1.0) 09.22.2005
• 3
(This specification is subject to change without further notice)
ELAN [ ELAN MICROELECTRONICS CORP ]
