GETATKBD

Action

Reads a key from a PC AT keyboard.

 

 

Syntax

var = GETATKBD()

 

 

Remarks

var	The variable that is assigned with the key read from the keyboard.   It may be a byte or a string variable. When no key is pressed a 0 will be returned.

 

The GETAKBD() function needs 2 input pins and a translation table for the keys. You can read more about this at theCONFIG KEYBOARD compiler directive.

 

The Getatkbd function will wait for a pressed key. When you want to escape from the waiting loop you can set the ERR bit from an interrupt routine for example.

 

Getatkbd is using 2 bits from register R6 : bit 4 and 5 are used to hold the shift and control key status.

 

 

AT KEYBOARD SCANCODES

 

Table reprinted with permission of Adam Chapweske

 

http://panda.cs.ndsu.nodak.edu/~achapwes

KEY	MAKE	BREAK		KEY	MAKE	BREAK		KEY	MAKE	BREAK
A	1C	F0,1C		9	46	F0,46		[	54	FO,54
B	32	F0,32		`	0E	F0,0E		INSERT	E0,70	E0,F0,70
C	21	F0,21		-	4E	F0,4E		HOME	E0,6C	E0,F0,6C
D	23	F0,23		=	55	FO,55		PG UP	E0,7D	E0,F0,7D
E	24	F0,24		\	5D	F0,5D		DELETE	E0,71	E0,F0,71
F	2B	F0,2B		BKSP	66	F0,66		END	E0,69	E0,F0,69
G	34	F0,34		SPACE	29	F0,29		PG DN	E0,7A	E0,F0,7A
H	33	F0,33		TAB	0D	F0,0D		U ARROW	E0,75	E0,F0,75
I	43	F0,43		CAPS	58	F0,58		L ARROW	E0,6B	E0,F0,6B
J	3B	F0,3B		L SHFT	12	FO,12		D ARROW	E0,72	E0,F0,72
K	42	F0,42		L CTRL	14	FO,14		R ARROW	E0,74	E0,F0,74
L	4B	F0,4B		L GUI	E0,1F	E0,F0,1F		NUM	77	F0,77
M	3A	F0,3A		L ALT	11	F0,11		KP /	E0,4A	E0,F0,4A
N	31	F0,31		R SHFT	59	F0,59		KP *	7C	F0,7C
O	44	F0,44		R CTRL	E0,14	E0,F0,14		KP -	7B	F0,7B
P	4D	F0,4D		R GUI	E0,27	E0,F0,27		KP +	79	F0,79
Q	15	F0,15		R ALT	E0,11	E0,F0,11		KP EN	E0,5A	E0,F0,5A
R	2D	F0,2D		APPS	E0,2F	E0,F0,2F		KP .	71	F0,71
S	1B	F0,1B		ENTER	5A	F0,5A		KP 0	70	F0,70
T	2C	F0,2C		ESC	76	F0,76		KP 1	69	F0,69
U	3C	F0,3C		F1	05	F0,05		KP 2	72	F0,72
V	2A	F0,2A		F2	06	F0,06		KP 3	7A	F0,7A
W	1D	F0,1D		F3	04	F0,04		KP 4	6B	F0,6B
X	22	F0,22		F4	0C	F0,0C		KP 5	73	F0,73
Y	35	F0,35		F5	03	F0,03		KP 6	74	F0,74
Z	1A	F0,1A		F6	0B	F0,0B		KP 7	6C	F0,6C
0	45	F0,45		F7	83	F0,83		KP 8	75	F0,75
1	16	F0,16		F8	0A	F0,0A		KP 9	7D	F0,7D
2	1E	F0,1E		F9	01	F0,01		]	5B	F0,5B
3	26	F0,26		F10	09	F0,09			4C	F0,4C
4	25	F0,25		F11	78	F0,78		'	52	F0,52
5	2E	F0,2E		F12	07	F0,07		,	41	F0,41
6	36	F0,36		PRNT   SCRN	E0,12,   E0,7C	E0,F0,   7C,E0, F0,12		.	49	F0,49
7	3D	F0,3D		SCROLL	7E	F0,7E		/	4A	F0,4A
8	3E	F0,3E		PAUSE	E1,14,77,   E1,F0,14, F0,77	-NONE-

 

 

These are the usable scan codes from the keyboard. If you want to implement F1 , you look at the generated scan code : 05 hex. So in the table, at position 5+1=6, you write the value for F1.

 

In the sample program below, you can find the value 200. When you now press F1, the value form the table will be used so 200 will be returned.

 

 

See also

CONFIG KEYBOARD , GETATKBDRAW

 

 

Example

'-----------------------------------------------------------------------------------------
'name : getatkbd.bas
'copyright : (c) 1995-2005, MCS Electronics
'purpose : PC AT-KEYBOARD Sample
'micro : Mega48
'suited for demo : yes
'commercial addon needed : no
'-----------------------------------------------------------------------------------------
 
$regfile = "8535def.dat" ' specify the used micro
$crystal = 4000000 ' used crystal frequency
$baud = 19200 ' use baud rate
$hwstack = 32 ' default use 32 for the hardware stack
$swstack = 10 ' default use 10 for the SW stack
$framesize = 40 ' default use 40 for the frame space
 
'For this example :
'connect PC AT keyboard clock to PIND.2 on the 8535
'connect PC AT keyboard data to PIND.4 on the 8535
 
'The GetATKBD() function does not use an interrupt.
'But it waits until a key was pressed!
 
'configure the pins to use for the clock and data
'can be any pin that can serve as an input
'Keydata is the label of the key translation table
Config Keyboard = Pind.2 , Data = Pind.4 , Keydata = Keydata
 
'Dim some used variables
Dim S As String * 12
Dim B As Byte
 
'In this example we use SERIAL(COM) INPUT redirection
$serialinput = Kbdinput
 
'Show the program is running
Print "hello"
 
Do
'The following code is remarked but show how to use the GetATKBD() function
' B = Getatkbd() 'get a byte and store it into byte variable
'When no real key is pressed the result is 0
'So test if the result was > 0
' If B > 0 Then
' Print B ; Chr(b)
' End If
 
'The purpose of this sample was how to use a PC AT keyboard
'The input that normally comes from the serial port is redirected to the
'external keyboard so you use it to type
Input "Name " , S
'and show the result
Print S
'now wait for the F1 key , we defined the number 200 for F1 in the table
Do
 B = Getatkbd()
Loop Until B <> 0
Print B
Loop
End
 
'Since we do a redirection we call the routine from the redirection routine
'
Kbdinput:
'we come here when input is required from the COM port
'So we pass the key into R24 with the GetATkbd function
' We need some ASM code to save the registers used by the function
$asm
push r16 ; save used register
push r25
push r26
push r27
 
Kbdinput1:
rCall _getatkbd ; call the function
tst r24 ; check for zero
breq Kbdinput1 ; yes so try again
pop r27 ; we got a valid key so restore registers
pop r26
pop r25
pop r16
$end Asm
'just return
Return
 
'The tricky part is that you MUST include a normal call to the routine
'otherwise you get an error
'This is no clean solution and will be changed
B = Getatkbd()
 
'This is the key translation table
 
Keydata:
'normal keys lower case
Data 0 , 0 , 0 , 0 , 0 , 200 , 0 , 0 , 0 , 0 , 0 , 0 , 0 , 0 , &H5E , 0
Data 0 , 0 , 0 , 0 , 0 , 113 , 49 , 0 , 0 , 0 , 122 , 115 , 97 , 119 , 50 , 0
Data 0 , 99 , 120 , 100 , 101 , 52 , 51 , 0 , 0 , 32 , 118 , 102 , 116 , 114 , 53 , 0
Data 0 , 110 , 98 , 104 , 103 , 121 , 54 , 7 , 8 , 44 , 109 , 106 , 117 , 55 , 56 , 0
Data 0 , 44 , 107 , 105 , 111 , 48 , 57 , 0 , 0 , 46 , 45 , 108 , 48 , 112 , 43 , 0
Data 0 , 0 , 0 , 0 , 0 , 92 , 0 , 0 , 0 , 0 , 13 , 0 , 0 , 92 , 0 , 0
Data 0 , 60 , 0 , 0 , 0 , 0 , 8 , 0 , 0 , 49 , 0 , 52 , 55 , 0 , 0 , 0
Data 48 , 44 , 50 , 53 , 54 , 56 , 0 , 0 , 0 , 43 , 51 , 45 , 42 , 57 , 0 , 0
 
'shifted keys UPPER case
Data 0 , 0 , 0 , 0 , 0 , 0 , 0 , 0 , 0 , 0 , 0 , 0 , 0 , 0 , 0 , 0
Data 0 , 0 , 0 , 0 , 0 , 81 , 33 , 0 , 0 , 0 , 90 , 83 , 65 , 87 , 34 , 0
Data 0 , 67 , 88 , 68 , 69 , 0 , 35 , 0 , 0 , 32 , 86 , 70 , 84 , 82 , 37 , 0
Data 0 , 78 , 66 , 72 , 71 , 89 , 38 , 0 , 0 , 76 , 77 , 74 , 85 , 47 , 40 , 0
Data 0 , 59 , 75 , 73 , 79 , 61 , 41 , 0 , 0 , 58 , 95 , 76 , 48 , 80 , 63 , 0
Data 0 , 0 , 0 , 0 , 0 , 96 , 0 , 0 , 0 , 0 , 13 , 94 , 0 , 42 , 0 , 0
Data 0 , 62 , 0 , 0 , 0 , 8 , 0 , 0 , 49 , 0 , 52 , 55 , 0 , 0 , 0 , 0
Data 48 , 44 , 50 , 53 , 54 , 56 , 0 , 0 , 0 , 43 , 51 , 45 , 42 , 57 , 0 , 0

Languages	English • Deutsch