![background image](http://html.mh-extra.com/html/blue-chip/adc-42/adc-42_user-manual_2775482027.webp)
Input Connections
Page
19
Blue Chip Technology Ltd.
01271014.doc
Page 19
Ports
Bit
Hex
Decimal
0
01
1
1
02
2
2
04
4
3
08
8
2
4
10
16
5
20
32
6
40
64
7
80
128
4.3.1 Control Code Table
The following table gives a summary of the most commonly used ‘control
words’ which must be written to the control port to configure the 8255 before
using this module.
The 8255 can operate in one of 3 modes (mode 0-2).
In the first mode (mode 0 ) the 8255 provides simple I/O for 3, 8 bit ports. Data
is simply written to or read from a specified port (A, B or C) with out the use of
handshaking. The following Control Code Table assumes mode 0 is required.
Mode 1 enables the transfer of data to or from a specified 8 bit port (A or B) in
conjunction with strobes or handshaking signals.