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stunt
Account closed
Registered: Jul 2006
Posts: 48 |
Scan the keyboard
Guys,
Right now i'm still using kernal routine $ffe4 to scan the keyboard, but ofcourse I'd rather avoid using kernal routines. So Scout suggested me inastead to scan the keyboard matrix ($dc00 and $dc01) directly.
Now i have:
keyscanloop
lda $dc00 ; row
and #%00100000
bne continu
lda $dc01 ; collumn
and #%00000001
bne continu
jmp keyispressed
continu
jmp keyscanloop
keyispressed
...
But this doesnt seem to be working.
What am i doin wrong?
Stunt |
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Soren
Registered: Dec 2001
Posts: 547 |
That gets a bit tricky, as there is both left shift and right shift/shiftlock.
But there is a neat adress, $028d which can be used to check for shift/CTRL/Commodore
when it has value 01, a shift key is pressed, 02 -> commodore key is pressed. 04 -> ctrl is pressed.
And you can combine those values.
so possible you could first check for f7 by using dc00 and dc01, and then check if shift is pressed by using address $028d.
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stunt
Account closed
Registered: Jul 2006
Posts: 48 |
@ jeff: u rock. f8 is now working also :)) |
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enthusi
Registered: May 2004
Posts: 677 |
well 028d aint very helpful when you code the KB-scan to get rid of the kernal. sorry for being all negative and of little use. |
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stunt
Account closed
Registered: Jul 2006
Posts: 48 |
@ enthusi:
Please explain.
And please also tell me what is your solution then to read shift+key?
Stunt
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stunt
Account closed
Registered: Jul 2006
Posts: 48 |
What about scanning for both left and right shift?
U experts tell me what is the fastest option?
Maybe the fastest option is not to use shift/key combinations at all?
The thing is that i have to be careful, i have so many things to do per frame and yet so little rastertime:
Lots of sidparamters are updated realtime (at least 4 times per frame but if possible some parameters have to be updated like 8 or more times per frame), midi implementation still has to fit in (but i will probably rely on hardware a lot for the midipart) and also more than 1 sidchips are going to be adressed and updated in the future (right now pimping c64 by adding extrasidchip for 3+ voice polyphony) so i have to be very efficient with time. |
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enthusi
Registered: May 2004
Posts: 677 |
$028d is set (only) by kernal. Actually by the very same code more or less you want to avoid. And since Im in destructive mode I deliver no solution ;)
But no magic needed. Same concept. Only some combinations are tough or if you want to check shift OR shift-lock. A mere 2-keys at once can be sone the same way as you do it now. Just AND the values or check this forum in coding. I recall at least one thread about detecting 3 keys etc...
good luck |
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tlr
Registered: Sep 2003
Posts: 1790 |
How about this?
scan:
lda #$ff
sta $dc02
lda #$00
sta $dc03
ldy #0
lda #$fe
sc_lp1:
pha
sta $dc00
lda $dc01
sta tab,y
iny
pla
sec
rol
bcs sc_lp1
sta $dc00 ; =$ff
rts
tab:
ds.b 8
It will test each row, and store the result in tab.
Now you will have one '0' bit for each key in tab (row 0 -> 7).
Due to how the matrix works, not all combinations of keys can be detected properly.
Complete scanner program for the C64 (and DTV):
http://www.kahlin.net/daniel/dtv/keyjoy.php
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Soren
Registered: Dec 2001
Posts: 547 |
using tables is a good idea. There must be several ways to do
that, depending on your needs.
But just thought about the F8-thing.. you could do a check for right shift+f7
and a check for left shift+f7....
just to be sure.
;)
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enthusi
Registered: May 2004
Posts: 677 |
and if you need a table, dont generate it :)
copy it:
http://www.tkk.fi/Misc/cbm/docs/c64-diss.html#EB79 |
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stunt
Account closed
Registered: Jul 2006
Posts: 48 |
Quote: and if you need a table, dont generate it :)
copy it:
http://www.tkk.fi/Misc/cbm/docs/c64-diss.html#EB79
Hey guys all this help is great.
I wish one of you coders would show the same dedication to the question that is formulated in the last post of in my other recent thread here about modulation: --> How to players and trackers usually deal with these modulation issues? --> Bit-scaling? (sid related, but not nescesarily, not a question related to the battlestar galactica music btw;-)
(scroll down to the last post)
Stunt |
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