Difference between revisions of "Programming:Keyboard scanning"
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This is a routine which scans one line of the keyboard directly. It is approximately 8% faster then the firmware routine and doesn't enable interrupts. | This is a routine which scans one line of the keyboard directly. It is approximately 8% faster then the firmware routine and doesn't enable interrupts. | ||
| − | '''Input:''' A = ''line (&40 - &49) | + | '''Input:''' A = ''line (&40 - &49)'' |
'''Output:''' A = ''hardware keyboard value'' | '''Output:''' A = ''hardware keyboard value'' | ||
'''Destroyed:''' BC | '''Destroyed:''' BC | ||
| + | <pre>LD A,kbdline ; from 0 to 9 with bdir/bc1=01 | ||
| + | LD BC,#F782 ; PPI port A out /C out | ||
| + | OUT (C),C | ||
| + | LD BC,#F40E ; Select Ay reg 14 on ppi port A | ||
| + | OUT (C),C | ||
| + | LD BC,#F6CO ; This value is an AY index (R14) | ||
| + | OUT (C),C | ||
| + | OUT (C),0 ; Validate!! | ||
| + | LD BC,#F792 ; PPI port A in/C out | ||
| + | OUT (C),C | ||
| + | DEC B | ||
| + | OUT (C),A ; Send KbdLine on reg 14 AY through ppi port A | ||
| + | LD B,#F4 ; Read ppi port A | ||
| + | IN A,(C) ; e.g. AY R14 (AY port A) | ||
| + | LD BC,#F782 ; PPI port A out / C out | ||
| + | OUT (C),C | ||
| + | DEC B ; Reset PPI Write | ||
| + | OUT (C),0 | ||
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| + | Now check for the value from the table e.g. with''''bit x,A''''and a condition e.g.''''jp z,xxxx''''or''''call z,xxxx'''' | ||
| + | </pre> | ||
Please note: | Please note: | ||
| + | |||
* Bit = 0: Key is pressed | * Bit = 0: Key is pressed | ||
* Bit = 1: Key is not pressed | * Bit = 1: Key is not pressed | ||
Revision as of 05:07, 27 November 2007
Hardware scancode table
| Bit: Line |
7 | 6 | 5 | 4 | 3 | 2 | 1 | 0 |
| &40 | F Dot | ENTER | F3 | F6 | F9 | CURDOWN | CURRIGHT | CURUP |
| &41 | F0 | F2 | F1 | F5 | F8 | F7 | COPY | CURLEFT |
| &42 | CONTROL | \ | SHIFT | F4 | ] | RETURN | [ | CLR |
| &43 | . | / | : | ; | P | @ | - | ^ |
| &44 | , | M | K | L | I | O | 9 | 0 |
| &45 | SPACE | N | J | H | Y | U | 7 | 8 |
| &46 | V | B | F | G | T | R | 5 | 6 |
| &47 | X | C | D | S | W | E | 3 | 4 |
| &48 | Z | CAPSLOCK | A | TAB | Q | ESC | 2 | 1 |
| &49 | DEL | - | - | - | - | - | - | - |
One line scanning routine
This is a routine which scans one line of the keyboard directly. It is approximately 8% faster then the firmware routine and doesn't enable interrupts.
Input: A = line (&40 - &49)
Output: A = hardware keyboard value
Destroyed: BC
LD A,kbdline ; from 0 to 9 with bdir/bc1=01 LD BC,#F782 ; PPI port A out /C out OUT (C),C LD BC,#F40E ; Select Ay reg 14 on ppi port A OUT (C),C LD BC,#F6CO ; This value is an AY index (R14) OUT (C),C OUT (C),0 ; Validate!! LD BC,#F792 ; PPI port A in/C out OUT (C),C DEC B OUT (C),A ; Send KbdLine on reg 14 AY through ppi port A LD B,#F4 ; Read ppi port A IN A,(C) ; e.g. AY R14 (AY port A) LD BC,#F782 ; PPI port A out / C out OUT (C),C DEC B ; Reset PPI Write OUT (C),0 Now check for the value from the table e.g. with''''bit x,A''''and a condition e.g.''''jp z,xxxx''''or''''call z,xxxx''''
Please note:
- Bit = 0: Key is pressed
- Bit = 1: Key is not pressed
Complete keyboard scanning routine
This routine scans the complete keyboard and writes all key status bits in a map.
keymap ds 10 ;map with 10*8 = 80 key status bits (bit=0 key is pressed)
keyscan di ;1 ##%%## C P C VERSION ##%%##
ld hl,keymap ;3
ld bc,#f782 ;3
out (c),c ;4
ld bc,#f40e ;3
ld e,b ;1
out (c),c ;4
ld bc,#f6c0 ;3
ld d,b ;1
out (c),c ;4
ld c,0 ;2
out (c),c ;4
ld bc,#f792 ;3
out (c),c ;4
ld a,#40 ;2
ld c,#4a ;2 44
loop ld b,d ;1
out (c),a ;4 select line
ld b,e ;1
ini ;5 read bits and write into KEYMAP
inc a ;1
cp c ;1
jr c,loop ;2/3 9*16+1*15=159
ld bc,#f782 ;3
out (c),c ;4
ei ;1 8 =211 microseconds
ret
