Masking pins

A PORT usually have 8 output / input pins. Sometimes we need to `scan' a PORT to check which pins are high and which pins are low.

Temp will return a decimal value according to the logic binary of that PORT. What happens when we need to `scan' only the first 4 pins of a PORT or whatever pins on a PORT depending on the wiring and you need to use the rest as input or outputs?

If the required pins are not masked, then all the PORT will be read, and a wrong value will be read depending on what state the `not scaned' pins are. If you mask a part of a PORT, then you only read the pins you have masked.

I found a thread which is very useful when it comes to mask pins of a PORT. Follow this link to see how masking can be done.

http://www.protonbasic.co.uk/showthr...011#post454011

Joseph