8-Bit CMOS Microcontrollers User's Manual

S3F80JB PRODUCT OVERVIEW
1-11
PIN CIRCUITS (Continued)
V DD
Pull-up
Resistor
(55k
Ω -Typ)
V DD
V SS
Noise
Filter
INPUT/OUTPUT
Pull-up
Enable
Data
Output Disable
Normal
Input
Open-Drain
Figure 1-6. Pin Circuit Type 2 (Port 1, Port4, P3.4 and P3.5)