W921C880 查看數據表（PDF） - Winbond

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W921C880

4-BIT MICROCONTROLLER

Winbond 

W921E880A/W921C880

* PC.0−PC.3:

* PD.0−PD.3:

* PE.0−PE.3:

* PF.0−PF.3:

Normal function is the same as port P0

Normal I/O pins only.

Normal function is the same as port P0

Normal I/O pins only.

Normal function is the same as port P0

Normal I/O pins only.

Normal function is the same as port P0

Normal I/O pins only.

Normal function is the same as port P0

6.5.1 I/O Pull High and Open Drain Control

Some of the above I/O ports can be set up with a pull-high resistor or as an open drain. The user can

program the I/O through the special register so that the I/O can have a pull-high resistor or open drain

characteristics.

All pull-high resistors in the following table are 400 KΩ in a 3.0 voltage test condition. After a power

on reset the following special reg. will all reset to "0000".

* P4.0−P4.3:

P4PH REG: (ADDRESS = 003H)

(Default data = 0H)

b3

b2

b1

b0

P4TP REG: (ADDRESS = 004H)

(Default data = 0H)

0: P4.0 without pull-high resistor

1: P4.0 with pull-high resistor

0: P4.1 without pull-high resistor

1: P4.1 with pull-high resistor

0: P4.2 without pull-high resistor

1: P4.2 with pull-high resistor

0: P4.3 without pull-high resistor

1: P4.3 with pull-high resistor

b3

b2

b1

b0

0: P4.0 work as CMOS type

1: P4.0 work as Open-drain type

0: P4.1 work as CMOS type

1: P4.1 work as Open-drain type

0: P4.2 work as CMOS type

1: P4.2 work as Open-drain type

0: P4.3 work as CMOS type

1: P4.3 work as Open-drain type

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Publication Release Date: July 1999

Revision A3

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