W921E400 Просмотр технического описания (PDF) - Winbond

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W921E400

4-BIT MICROCONTROLLER

Winbond 

W921E400A/W921C400

The input or output mode of port A to port B only can be decided by I/O instructions. For example,

MOV A, Px will change Px to input mode and MOV Px, A will change it to output mode.

6.5.1 Normal/Special function selection of I/O

Some of the I/O ports can be programed to special function via special control register. The detail

functions are as follows.

• P2.0 to P2.1: Two 15 mA sink current normal I/O pins only

• P3.0 to P3.3: Multi-function I/O pins (selected by P3IO register)

− Normal function I/O pins

− Special function input pins

P3IO register: (address = 00FH, default data = 0H)

b3

b2

b1

b0

0: Normal I/O P3.0

1: Analog input pin 0 (ANI0)

0: Normal I/O P3.1

1: Analog input pin 1 (ANI1)

0: Normal I/O P3.2

1: Analog input pin 2 (ANI2)

0: Normal I/O P3.3

1: Analog input pin 3 (ANI3)

• P4.2 to P4.3: Multi-function I/O pins (selected by P4IO register)

− Normal function I/O pins

− Special function input pins: (All the pins are falling edge active)

P4IO register: (address = 010H, default data = 0H)

b3

b2

b1

b0

Reserved

Reserved

0: Normal I/O P4.2, interrupt disable

1: Interrupt port P4.2

0: Normal I/O P4.3, interrupt disable

1: INT0

• P5.1: Multi-function I/O pins (selected by P5IO register)

− Normal function I/O pins

− Special function I/O pins

- 14 -

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