Mikroelektronika MIKROE-350 Datenbogen

304

- SOFTWARE AND HARDWARE SOLUTIONS FOR EMBEDDED WORLD

CHAPTER 6

sub function Ps2_Key_Read(dim byref value as byte, dim byref spe-
cial 

as byte, dim byref pressed as byte) as byte

- 

1

if reading of a key from the keyboard was successful 

- 

0

if no key was pressed 

The function retrieves information on key pressed.

Parameters : 

- 

value:

holds the value of the key pressed. For characters, numerals, punctu-

ation marks, and space value will store the appropriate ASCII code. Routine
“recognizes” the function of Shift and Caps Lock, and behaves appropriately.
For special function keys see Special Function Keys Table. 
- 

special:

is a flag for special function keys (F1, Enter, Esc, etc). If key

pressed is one of these, 

special

will be set to 1, otherwise 0. 

- 

pressed:

is set to 1 if the key is pressed, and 0 if it is released. 

PS/2 keyboard needs to be initialized. See Ps2_Config routine.

dim value, special, pressed as byte
...
do {

if (Ps2_Key_Read(value, special, pressed)) then

if ((value = 13) and (special = 1)) then

loop until (0=1)