Only 75 s is required to read 128 digital input pins and to write to 128 output pins.

Had a minor change to the protection/buffering of the input pins.

The output pin value placed is then propagated to any input pins that are connected to it.

It has 8 input pins, usually labelled as D7.

For input, the system simply reads pushbuttons connected to its input pins.

Enhanced I/O port with 8 output and 4 input pins.

A pin connection appears as an arrow connecting the output pin to the input pin.

The binary value expressed on these selector pins determines the selected input pin.

The d.c. link between output pin 6 and inverting input pin 2 is known as 'negative feedback'.

The 20V8 shares the same architecture but has more input pins.