Product specifications

Appendix D
7.4
Keyboard Layout
The diagram below is a logical map showing how the keyboard is laid out from the
machine hardware point of view.
Outputting the correct sense value via port 5 into the keyboard matrix and reading the
correct value from port 5 as a scan byte is discussed in more detail in section 5.
A table summary of the values is given in Appendix E.
Lower case values are detected by looking at the shift key.
(Illus 14 – Diagram of keyboard layout)
Appendix E
7.5
Table Summary of Keyboard Sense/Scan Values
To use this table please refer to section 5 and Appendix D.
The table summary does not cover all combinations of keys but only:
1. Alphabetic A to Z
2. Digits 0 to 9
3. Cursor keys and home key
Using this table and the diagram above it is easy to work out any other values you
may need.
Detect Key Port 5 Port 5
Key Sense Value Scan Value
Hex Decimal Hex Decimal
A £DF £FE
B £7F £FB
C £7F £FD
D £DF £FD
E £7F £FD
F £EF £FB
G £DF £FB
H £EF £F7
I £FB £EF
J £DF £F7
K £EF £EF
L £DF £EF
M £7F £7F
N £BF £F7
O £F7 £EF
P £FB £DF