153 lines
3.7 KiB
NASM
153 lines
3.7 KiB
NASM
; kbd
|
|
;
|
|
; Control TI-84+'s keyboard.
|
|
;
|
|
; *** Constants ***
|
|
.equ KBD_PORT 0x01
|
|
|
|
; Keys that have a special meaning in GetC. All >= 0x80. They are interpreted
|
|
; by GetC directly and are never returned as-is.
|
|
.equ KBD_KEY_ALPHA 0x80
|
|
.equ KBD_KEY_2ND 0x81
|
|
|
|
; *** Variables ***
|
|
; active long-term modifiers, such as a-lock
|
|
; bit 0: A-Lock
|
|
.equ KBD_MODS KBD_RAMSTART
|
|
.equ KBD_RAMEND @+1
|
|
|
|
; *** Code ***
|
|
|
|
kbdInit:
|
|
xor a
|
|
ld (KBD_MODS), a
|
|
ret
|
|
|
|
; Wait for a digit to be pressed and sets the A register ASCII value
|
|
; corresponding to that key press.
|
|
;
|
|
; This routine waits for a key to be pressed, but before that, it waits for
|
|
; all keys to be de-pressed. It does that to ensure that two calls to
|
|
; waitForKey only go through after two actual key presses (otherwise, the user
|
|
; doesn't have enough time to de-press the button before the next waitForKey
|
|
; routine registers the same key press as a second one).
|
|
;
|
|
; Sending 0xff to the port resets the keyboard, and then we have to send groups
|
|
; we want to "listen" to, with a 0 in the group bit. Thus, to know if *any* key
|
|
; is pressed, we send 0xff to reset the keypad, then 0x00 to select all groups,
|
|
; if the result isn't 0xff, at least one key is pressed.
|
|
kbdGetC:
|
|
push bc
|
|
push hl
|
|
|
|
; During this GetC loop, register C holds the modificators
|
|
; bit 0: Alpha
|
|
; bit 1: 2nd
|
|
; Initial value should be zero, but if A-Lock is on, it's 1
|
|
ld a, (KBD_MODS)
|
|
and 1
|
|
ld c, a
|
|
|
|
; loop until a digit is pressed
|
|
.loop:
|
|
ld hl, .dtbl
|
|
; we go through the 7 rows of the table
|
|
ld b, 7
|
|
; is alpha mod enabled?
|
|
bit 0, c
|
|
jr z, .inner ; unset? skip next
|
|
ld hl, .atbl ; set? we're in alpha mode
|
|
.inner:
|
|
ld a, (hl) ; group mask
|
|
call .get
|
|
cp 0xff
|
|
jr nz, .something
|
|
; nothing for that group, let's scan the next group
|
|
ld a, 9
|
|
call addHL ; go to next row
|
|
djnz .inner
|
|
; found nothing, loop
|
|
jr .loop
|
|
.something:
|
|
; We have something on that row! Let's find out which char. Register A
|
|
; currently contains a mask with the pressed char bit unset.
|
|
ld b, 8
|
|
inc hl
|
|
.findchar:
|
|
rrca ; is next bit unset?
|
|
jr nc, .gotit ; yes? we have our char!
|
|
inc hl
|
|
djnz .findchar
|
|
.gotit:
|
|
ld a, (hl)
|
|
or a ; is char 0?
|
|
jr z, .loop ; yes? unsupported. loop.
|
|
call .debounce
|
|
cp KBD_KEY_ALPHA
|
|
jr c, .end ; A < 0x80? valid char, return it.
|
|
jr z, .handleAlpha
|
|
cp KBD_KEY_2ND
|
|
jr z, .handle2nd
|
|
jp .loop
|
|
.handleAlpha:
|
|
set 0, c
|
|
bit 1, c ; 2nd set?
|
|
jp z, .loop ; unset? loop
|
|
; we've just hit Alpha with 2nd set. Toggle A-Lock and set Alpha to
|
|
; the value A-Lock has.
|
|
ld a, (KBD_MODS)
|
|
xor 1
|
|
ld (KBD_MODS), a
|
|
ld c, a
|
|
jp .loop
|
|
.handle2nd:
|
|
set 1, c
|
|
jp .loop
|
|
|
|
.end:
|
|
pop hl
|
|
pop bc
|
|
ret
|
|
.get:
|
|
ex af, af'
|
|
ld a, 0xff
|
|
di
|
|
out (KBD_PORT), a
|
|
ex af, af'
|
|
out (KBD_PORT), a
|
|
in a, (KBD_PORT)
|
|
ei
|
|
ret
|
|
.debounce:
|
|
; wait until all keys are de-pressed
|
|
push af ; --> lvl 1
|
|
.wait:
|
|
xor a
|
|
call .get
|
|
inc a ; if a was 0xff, will become 0 (nz test)
|
|
jr nz, .wait ; non-zero? something is pressed
|
|
|
|
pop af ; <-- lvl 1
|
|
ret
|
|
|
|
; digits table. each row represents a group. first item is group mask.
|
|
; 0 means unsupported. no group 7 because it has no keys.
|
|
.dtbl:
|
|
.db 0xfe, 0, 0, 0, 0, 0, 0, 0, 0
|
|
.db 0xfd, 0x0d, '+' ,'-' ,'*', '/', '^', 0, 0
|
|
.db 0xfb, 0, '3', '6', '9', ')', 0, 0, 0
|
|
.db 0xf7, '.', '2', '5', '8', '(', 0, 0, 0
|
|
.db 0xef, '0', '1', '4', '7', ',', 0, 0, 0
|
|
.db 0xdf, 0, 0, 0, 0, 0, 0, 0, KBD_KEY_ALPHA
|
|
.db 0xbf, 0, 0, 0, 0, 0, KBD_KEY_2ND, 0, 0x7f
|
|
|
|
; alpha table. same as .dtbl, for when we're in alpha mode.
|
|
.atbl:
|
|
.db 0xfe, 0, 0, 0, 0, 0, 0, 0, 0
|
|
.db 0xfd, 0x0d, '"' ,'W' ,'R', 'M', 'H', 0, 0
|
|
.db 0xfb, '?', 0, 'V', 'Q', 'L', 'G', 0, 0
|
|
.db 0xf7, ':', 'Z', 'U', 'P', 'K', 'F', 'C', 0
|
|
.db 0xef, '_', 'Y', 'T', 'O', 'J', 'E', 'B', 0
|
|
.db 0xdf, 0, 'X', 'S', 'N', 'I', 'D', 'A', KBD_KEY_ALPHA
|
|
.db 0xbf, 0, 0, 0, 0, 0, KBD_KEY_2ND, 0, 0x7f
|