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S3C9454B/F9454B
I/O PORTS
9-7
PORT 1
Port 1, is a 3-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). In addition, you can configure a pull-up and
pull-down resistor to individual pin using control register settings. It is designed for high-current functions such as
LED direct drive.
P1.0, P1.1 are used for oscillator input/output by smart option. Also, P1.2 is used for RESET pin by smart option.
One control register is used to control port 1: P1CON (E9H).
You address port 1 bits directly by writing or reading the port 1 data register, P1 (E1H). When you use external
oscillator, P1.0, P1.1 must be set to output port to prevent current consumption.
V
DD
In/Out
Output DIsable
(input mode)
P1 Data
V
DD
Pull-Up Register
(50 k
Ω
typical)
Circuit type A
Input Data
Pull-Down
Enable
Pull-up
Enable
Open-Drain
MUX
D0
D1
X
IN
, X
OUT
or RESET
NOTE:
I/O pins have protection diodes
through V
DD
and V
SS
.
MUX
Smart option
Pull-Down Register
(50 k
Ω
typical)
Mode
Input Data
Output
Input
D0
D1
Figure 9-6. Port 1 Circuit Diagram
Summary of Contents for S3C9454B
Page 1: ...S3C9454B F9454B 8 BIT CMOS MICROCONTROLLER USER S MANUAL Revision 1 ...
Page 25: ...PRODUCT OVERVIEW S3C9454B F9454B 1 10 NOTES ...
Page 35: ...ADDRESS SPACES S3C9454B F9454B 2 10 NOTES ...
Page 65: ...CONTROL REGISTERS S3C9454B F9454B 4 18 NOTES ...
Page 123: ...CLOCK CIRCUIT S3C9454B F9454B 7 4 NOTES ...
Page 133: ...RESET and POWER DOWN S39454B F9454B 8 10 NOTES ...
Page 145: ...I O PORTS S3C9454B F9454B 9 12 NOTES ...
Page 173: ...A D CONVERTER S3C9454B F9454B 12 8 NOTES ...
Page 183: ...ELECTRICAL DATA S3C9454B F9454B 13 10 NOTES ...