Panasonic F77G, MN101C77C user manual Port 2 IV

Models: F77G MN101C77C

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Chapter 4 I/O Ports

4-4

Port 2

4-4-1 Description

„General Port Setup

Each bit of the port 2 control I/O direction register (P2DIR) can be set individually to set pins as input or output. The control flag of the port 2 direction control register (P2DIR) should be set to "1" for output mode, and "0" for input mode.

To read input data of pin, set the control flag of the port 2 direction control register (P2DIR) to "0" and read the value of the port 2 input register (P2IN).

To output data to pin, set the control flag of the port 2 direction control register (P2DIR) to "1" and write the value of the port 2 output register (P2OUT).

P27 is reset pin. When the software is reset, write the bp7 of the port 2 output register (P2OUT) to "0".

Except P27, each bit can be set individually whether pull-up resistor is added or not, byt the port 2 pull-up resistor control register (P2PLU). When the control flag of the port 2 pull-up resistor control register (P2PLU) is set to "1", pull-up resistor is added. P27 is always added pull-up resistor.

„Special Function Pin Setup

P20 to P24 are used as external interrupt pins, as well.

P21 is used as an input pin for external interrupt and AC zero-cross. To read data of AC zero-cross, set the bp7 of the noise filter control register (NFCTR0) to "1" and read the value of the port 2 input register (P2IN).

Port 2 IV - 17

Page 167
Image 167
Panasonic F77G, MN101C77C user manual Port 2 IV