Samsung S3C9454B User Manual page 142

S3C9454B/F9454B
PORT 2
Port 2 is a 7-bit I/O port with individually configurable pins. It can be used for general I/O port (schmitt trigger input
mode, push-pull output mode or N-channel open-drain output mode). You can also use some pins of port 2 ADC
input, CLO output and T0 clock output. In addition, you can configure a pull-up resistor to individual pins using
control register settings. It is designed for high-current functions such as LED direct drive.
You address port 2 bits directly by writing or reading the port 2 data register, P2 (E2H). The port 2 control register,
P2CONH and P2CONL is located at addresses EAH, EBH respectively.
Pull-up
Enable
CLO, T0
P0 Data
Output DIsable
(input mode)
Input Data
to ADC
NOTE:
Open-Drain
P2CONH/L
M
U
X
MUX
I/O pins have protection diodes
through V and V .
DD SS
Figure 9-8. Port 2 Circuit Diagram
V
DD
D1
D0
Circuit Type A
Mode
Output
Input
V
DD
Pull-up register
(50 kΩ typical)
In/Out
Input Data
D0
D1
I/O PORTS
9-9