711 lines
31 KiB
Plaintext
711 lines
31 KiB
Plaintext
''***************************************
|
|
''* TV Driver v1.1 *
|
|
''* Author: Chip Gracey *
|
|
''* Copyright (c) 2004 Parallax, Inc. *
|
|
''* See end of file for terms of use. *
|
|
''***************************************
|
|
|
|
' v1.0 - 01 May 2006 - original version
|
|
' v1.1 - 17 May 2006 - pixel tile size can now be 16 x 32 to enable more efficient
|
|
' character displays utilizing the internal font - see 'tv_mode'
|
|
|
|
|
|
CON
|
|
|
|
fntsc = 3_579_545 'NTSC color frequency
|
|
lntsc = 3640 'NTSC color cycles per line * 16
|
|
sntsc = 624 'NTSC color cycles per sync * 16
|
|
|
|
fpal = 4_433_618 'PAL color frequency
|
|
lpal = 4540 'PAL color cycles per line * 16
|
|
spal = 848 'PAL color cycles per sync * 16
|
|
|
|
paramcount = 14
|
|
colortable = $180 'start of colortable inside cog
|
|
|
|
|
|
VAR
|
|
|
|
long cog
|
|
|
|
|
|
PUB start(tvptr) : okay
|
|
|
|
'' Start TV driver - starts a cog
|
|
'' returns false if no cog available
|
|
''
|
|
'' tvptr = pointer to TV parameters
|
|
|
|
stop
|
|
okay := cog := cognew(@entry, tvptr) + 1
|
|
|
|
|
|
PUB stop
|
|
|
|
'' Stop TV driver - frees a cog
|
|
|
|
if cog
|
|
cogstop(cog~ - 1)
|
|
|
|
|
|
DAT
|
|
|
|
'*******************************
|
|
'* Assembly language TV driver *
|
|
'*******************************
|
|
|
|
org
|
|
'
|
|
'
|
|
' Entry
|
|
'
|
|
entry mov taskptr,#tasks 'reset tasks
|
|
|
|
mov x,#10 'perform task sections initially
|
|
:init jmpret taskret,taskptr
|
|
djnz x,#:init
|
|
'
|
|
'
|
|
' Superfield
|
|
'
|
|
superfield mov taskptr,#tasks 'reset tasks
|
|
|
|
test _mode,#%0001 wc 'if ntsc, set phaseflip
|
|
if_nc mov phaseflip,phasemask
|
|
|
|
test _mode,#%0010 wz 'get interlace into nz
|
|
'
|
|
'
|
|
' Field
|
|
'
|
|
field mov x,vinv 'do invisible back porch lines
|
|
:black call #hsync 'do hsync
|
|
waitvid burst,sync_high2 'do black
|
|
jmpret taskret,taskptr 'call task section (z undisturbed)
|
|
djnz x,#:black 'another black line?
|
|
|
|
wrlong visible,par 'set status to visible
|
|
|
|
mov x,vb 'do visible back porch lines
|
|
call #blank_lines
|
|
|
|
mov screen,_screen 'point to first tile (upper-leftmost)
|
|
mov y,_vt 'set vertical tiles
|
|
:line mov vx,_vx 'set vertical expand
|
|
:vert if_z xor interlace,#1 'interlace skip?
|
|
if_z tjz interlace,#:skip
|
|
|
|
call #hsync 'do hsync
|
|
|
|
mov vscl,hb 'do visible back porch pixels
|
|
xor tile,colortable
|
|
waitvid tile,#0
|
|
|
|
mov x,_ht 'set horizontal tiles
|
|
mov vscl,hx 'set horizontal expand
|
|
|
|
:tile rdword tile,screen 'read tile
|
|
or tile,line 'set pointer bits into tile
|
|
rol tile,#6 'read tile pixels
|
|
rdlong pixels,tile '(2 instructions between reads)
|
|
shr tile,#10+6 'set tile colors
|
|
movs :color,tile
|
|
add screen,#2 'point to next tile
|
|
mov tile,phaseflip
|
|
:color xor tile,colortable
|
|
waitvid tile,pixels 'pass colors and pixels to video
|
|
djnz x,#:tile 'another tile?
|
|
|
|
sub screen,hc2x 'repoint to first tile in same line
|
|
|
|
mov vscl,hf 'do visible front porch pixels
|
|
mov tile,phaseflip
|
|
xor tile,colortable
|
|
waitvid tile,#0
|
|
|
|
:skip djnz vx,#:vert 'vertical expand?
|
|
ror line,linerot 'set next line
|
|
add line,lineadd wc
|
|
rol line,linerot
|
|
if_nc jmp #:line
|
|
add screen,hc2x 'point to first tile in next line
|
|
djnz y,#:line 'another tile line?
|
|
|
|
if_z xor interlace,#1 wz 'get interlace and field1 into z
|
|
|
|
test _mode,#%0001 wc 'do visible front porch lines
|
|
mov x,vf
|
|
if_nz_and_c add x,#1
|
|
call #blank_lines
|
|
|
|
if_nz wrlong invisible,par 'unless interlace and field1, set status to invisible
|
|
|
|
if_z_eq_c call #hsync 'if required, do short line
|
|
if_z_eq_c mov vscl,hrest
|
|
if_z_eq_c waitvid burst,sync_high2
|
|
if_z_eq_c xor phaseflip,phasemask
|
|
|
|
call #vsync_high 'do high vsync pulses
|
|
|
|
movs vsync1,#sync_low1 'do low vsync pulses
|
|
movs vsync2,#sync_low2
|
|
call #vsync_low
|
|
|
|
call #vsync_high 'do high vsync pulses
|
|
|
|
if_nz mov vscl,hhalf 'if odd frame, do half line
|
|
if_nz waitvid burst,sync_high2
|
|
|
|
if_z jmp #field 'if interlace and field1, display field2
|
|
jmp #superfield 'else, new superfield
|
|
'
|
|
'
|
|
' Blank lines
|
|
'
|
|
blank_lines call #hsync 'do hsync
|
|
|
|
xor tile,colortable 'do background
|
|
waitvid tile,#0
|
|
|
|
djnz x,#blank_lines
|
|
|
|
blank_lines_ret ret
|
|
'
|
|
'
|
|
' Horizontal sync
|
|
'
|
|
hsync test _mode,#%0001 wc 'if pal, toggle phaseflip
|
|
if_c xor phaseflip,phasemask
|
|
|
|
mov vscl,sync_scale1 'do hsync
|
|
mov tile,phaseflip
|
|
xor tile,burst
|
|
waitvid tile,sync_normal
|
|
|
|
mov vscl,hvis 'setup in case blank line
|
|
mov tile,phaseflip
|
|
|
|
hsync_ret ret
|
|
'
|
|
'
|
|
' Vertical sync
|
|
'
|
|
vsync_high movs vsync1,#sync_high1 'vertical sync
|
|
movs vsync2,#sync_high2
|
|
|
|
vsync_low mov x,vrep
|
|
|
|
vsyncx mov vscl,sync_scale1
|
|
vsync1 waitvid burst,sync_high1
|
|
|
|
mov vscl,sync_scale2
|
|
vsync2 waitvid burst,sync_high2
|
|
|
|
djnz x,#vsyncx
|
|
vsync_low_ret
|
|
vsync_high_ret ret
|
|
'
|
|
'
|
|
' Tasks - performed in sections during invisible back porch lines
|
|
'
|
|
tasks mov t1,par 'load parameters
|
|
movd :par,#_enable '(skip _status)
|
|
mov t2,#paramcount - 1
|
|
:load add t1,#4
|
|
:par rdlong 0,t1
|
|
add :par,d0
|
|
djnz t2,#:load '+119
|
|
|
|
mov t1,_pins 'set video pins and directions
|
|
test t1,#$08 wc
|
|
if_nc mov t2,pins0
|
|
if_c mov t2,pins1
|
|
test t1,#$40 wc
|
|
shr t1,#1
|
|
shl t1,#3
|
|
shr t2,t1
|
|
movs vcfg,t2
|
|
shr t1,#6
|
|
movd vcfg,t1
|
|
shl t1,#3
|
|
and t2,#$FF
|
|
shl t2,t1
|
|
if_nc mov dira,t2
|
|
if_nc mov dirb,#0
|
|
if_c mov dira,#0
|
|
if_c mov dirb,t2 '+18
|
|
|
|
tjz _enable,#disabled '+2, disabled?
|
|
|
|
jmpret taskptr,taskret '+1=140, break and return later
|
|
|
|
movs :rd,#wtab 'load ntsc/pal metrics from word table
|
|
movd :wr,#hvis
|
|
mov t1,#wtabx - wtab
|
|
test _mode,#%0001 wc
|
|
:rd mov t2,0
|
|
add :rd,#1
|
|
if_nc shl t2,#16
|
|
shr t2,#16
|
|
:wr mov 0,t2
|
|
add :wr,d0
|
|
djnz t1,#:rd '+54
|
|
|
|
if_nc movs :ltab,#ltab 'load ntsc/pal metrics from long table
|
|
if_c movs :ltab,#ltab+1
|
|
movd :ltab,#fcolor
|
|
mov t1,#(ltabx - ltab) >> 1
|
|
:ltab mov 0,0
|
|
add :ltab,d0s1
|
|
djnz t1,#:ltab '+17
|
|
|
|
rdlong t1,#0 'get CLKFREQ
|
|
shr t1,#1 'if CLKFREQ < 16MHz, cancel _broadcast
|
|
cmp t1,m8 wc
|
|
if_c mov _broadcast,#0
|
|
shr t1,#1 'if CLKFREQ < color frequency * 4, disable
|
|
cmp t1,fcolor wc
|
|
if_c jmp #disabled '+11
|
|
|
|
jmpret taskptr,taskret '+1=83, break and return later
|
|
|
|
mov t1,fcolor 'set ctra pll to fcolor * 16
|
|
call #divide 'if ntsc, set vco to fcolor * 32 (114.5454 MHz)
|
|
test _mode,#%0001 wc 'if pal, set vco to fcolor * 16 (70.9379 MHz)
|
|
if_c movi ctra,#%00001_111 'select fcolor * 16 output (ntsc=/2, pal=/1)
|
|
if_nc movi ctra,#%00001_110
|
|
if_nc shl t2,#1
|
|
mov frqa,t2 '+147
|
|
|
|
jmpret taskptr,taskret '+1=148, break and return later
|
|
|
|
mov t1,_broadcast 'set ctrb pll to _broadcast
|
|
mov t2,#0 'if 0, turn off ctrb
|
|
tjz t1,#:off
|
|
min t1,m8 'limit from 8MHz to 128MHz
|
|
max t1,m128
|
|
mov t2,#%00001_100 'adjust _broadcast to be within 4MHz-8MHz
|
|
:scale shr t1,#1 '(vco will be within 64MHz-128MHz)
|
|
cmp m8,t1 wc
|
|
if_c add t2,#%00000_001
|
|
if_c jmp #:scale
|
|
:off movi ctrb,t2
|
|
call #divide
|
|
mov frqb,t2 '+165
|
|
|
|
jmpret taskptr,taskret '+1=166, break and return later
|
|
|
|
mov t1,#%10100_000 'set video configuration
|
|
test _pins,#$01 wc '(swap broadcast/baseband output bits?)
|
|
if_c or t1,#%01000_000
|
|
test _mode,#%1000 wc '(strip chroma from broadcast?)
|
|
if_nc or t1,#%00010_000
|
|
test _mode,#%0100 wc '(strip chroma from baseband?)
|
|
if_nc or t1,#%00001_000
|
|
and _auralcog,#%111 '(set aural cog)
|
|
or t1,_auralcog
|
|
movi vcfg,t1 '+10
|
|
|
|
mov hx,_hx 'compute horizontal metrics
|
|
shl hx,#8
|
|
or hx,_hx
|
|
shl hx,#4
|
|
|
|
mov hc2x,_ht
|
|
shl hc2x,#1
|
|
|
|
mov t1,_ht
|
|
mov t2,_hx
|
|
call #multiply
|
|
mov hf,hvis
|
|
sub hf,t1
|
|
shr hf,#1 wc
|
|
mov hb,_ho
|
|
addx hb,hf
|
|
sub hf,_ho '+52
|
|
|
|
mov t1,_vt 'compute vertical metrics
|
|
mov t2,_vx
|
|
call #multiply
|
|
test _mode,#%10000 wc 'consider tile size
|
|
muxc linerot,#1
|
|
mov lineadd,lineinc
|
|
if_c shr lineadd,#1
|
|
if_c shl t1,#1
|
|
test _mode,#%0010 wc 'consider interlace
|
|
if_c shr t1,#1
|
|
mov vf,vvis
|
|
sub vf,t1
|
|
shr vf,#1 wc
|
|
neg vb,_vo
|
|
addx vb,vf
|
|
add vf,_vo '+53
|
|
|
|
xor _mode,#%0010 '+1, flip interlace bit for display
|
|
|
|
:colors jmpret taskptr,taskret '+1=117/160, break and return later
|
|
|
|
mov t1,#13 'load next 13 colors into colortable
|
|
:colorloop mov t2,:colorreg '5 times = 65 (all 64 colors loaded)
|
|
shr t2,#9-2
|
|
and t2,#$FC
|
|
add t2,_colors
|
|
:colorreg rdlong colortable,t2
|
|
add :colorreg,d0
|
|
andn :colorreg,d6
|
|
djnz t1,#:colorloop '+158
|
|
|
|
jmp #:colors '+1, keep loading colors
|
|
'
|
|
'
|
|
' Divide t1/CLKFREQ to get frqa or frqb value into t2
|
|
'
|
|
divide rdlong m1,#0 'get CLKFREQ
|
|
|
|
mov m2,#32+1
|
|
:loop cmpsub t1,m1 wc
|
|
rcl t2,#1
|
|
shl t1,#1
|
|
djnz m2,#:loop
|
|
|
|
divide_ret ret '+140
|
|
'
|
|
'
|
|
' Multiply t1 * t2 * 16 (t1, t2 = bytes)
|
|
'
|
|
multiply shl t2,#8+4-1
|
|
|
|
mov m1,#8
|
|
:loop shr t1,#1 wc
|
|
if_c add t1,t2
|
|
djnz m1,#:loop
|
|
|
|
multiply_ret ret '+37
|
|
'
|
|
'
|
|
' Disabled - reset status, nap ~4ms, try again
|
|
'
|
|
disabled mov ctra,#0 'reset ctra
|
|
mov ctrb,#0 'reset ctrb
|
|
mov vcfg,#0 'reset video
|
|
|
|
wrlong outa,par 'set status to disabled
|
|
|
|
rdlong t1,#0 'get CLKFREQ
|
|
shr t1,#8 'nap for ~4ms
|
|
min t1,#3
|
|
add t1,cnt
|
|
waitcnt t1,#0
|
|
|
|
jmp #entry 'reload parameters
|
|
'
|
|
'
|
|
' Initialized data
|
|
'
|
|
m8 long 8_000_000
|
|
m128 long 128_000_000
|
|
d0 long 1 << 9 << 0
|
|
d6 long 1 << 9 << 6
|
|
d0s1 long 1 << 9 << 0 + 1 << 1
|
|
interlace long 0
|
|
invisible long 1
|
|
visible long 2
|
|
phaseflip long $00000000
|
|
phasemask long $F0F0F0F0
|
|
line long $00060000
|
|
lineinc long $10000000
|
|
linerot long 0
|
|
pins0 long %11110000_01110000_00001111_00000111
|
|
pins1 long %11111111_11110111_01111111_01110111
|
|
sync_high1 long %0101010101010101010101_101010_0101
|
|
sync_high2 long %01010101010101010101010101010101 'used for black
|
|
sync_low1 long %1010101010101010101010101010_0101
|
|
sync_low2 long %01_101010101010101010101010101010
|
|
'
|
|
'
|
|
' NTSC/PAL metrics tables
|
|
' ntsc pal
|
|
' ----------------------------------------------
|
|
wtab word lntsc - sntsc, lpal - spal 'hvis
|
|
word lntsc / 2 - sntsc, lpal / 2 - spal 'hrest
|
|
word lntsc / 2, lpal / 2 'hhalf
|
|
word 243, 286 'vvis
|
|
word 10, 18 'vinv
|
|
word 6, 5 'vrep
|
|
word $02_8A, $02_AA 'burst
|
|
wtabx
|
|
ltab long fntsc 'fcolor
|
|
long fpal
|
|
long sntsc >> 4 << 12 + sntsc 'sync_scale1
|
|
long spal >> 4 << 12 + spal
|
|
long 67 << 12 + lntsc / 2 - sntsc 'sync_scale2
|
|
long 79 << 12 + lpal / 2 - spal
|
|
long %0101_00000000_01_10101010101010_0101 'sync_normal
|
|
long %010101_00000000_01_101010101010_0101
|
|
ltabx
|
|
'
|
|
'
|
|
' Uninitialized data
|
|
'
|
|
taskptr res 1 'tasks
|
|
taskret res 1
|
|
t1 res 1
|
|
t2 res 1
|
|
m1 res 1
|
|
m2 res 1
|
|
|
|
x res 1 'display
|
|
y res 1
|
|
hf res 1
|
|
hb res 1
|
|
vf res 1
|
|
vb res 1
|
|
hx res 1
|
|
vx res 1
|
|
hc2x res 1
|
|
screen res 1
|
|
tile res 1
|
|
pixels res 1
|
|
lineadd res 1
|
|
|
|
hvis res 1 'loaded from word table
|
|
hrest res 1
|
|
hhalf res 1
|
|
vvis res 1
|
|
vinv res 1
|
|
vrep res 1
|
|
burst res 1
|
|
|
|
fcolor res 1 'loaded from long table
|
|
sync_scale1 res 1
|
|
sync_scale2 res 1
|
|
sync_normal res 1
|
|
'
|
|
'
|
|
' Parameter buffer
|
|
'
|
|
_enable res 1 '0/non-0 read-only
|
|
_pins res 1 '%pppmmmm read-only
|
|
_mode res 1 '%tccip read-only
|
|
_screen res 1 '@word read-only
|
|
_colors res 1 '@long read-only
|
|
_ht res 1 '1+ read-only
|
|
_vt res 1 '1+ read-only
|
|
_hx res 1 '4+ read-only
|
|
_vx res 1 '1+ read-only
|
|
_ho res 1 '0+- read-only
|
|
_vo res 1 '0+- read-only
|
|
_broadcast res 1 '0+ read-only
|
|
_auralcog res 1 '0-7 read-only
|
|
|
|
fit colortable 'fit underneath colortable ($180-$1BF)
|
|
''
|
|
''___
|
|
''VAR 'TV parameters - 14 contiguous longs
|
|
''
|
|
'' long tv_status '0/1/2 = off/invisible/visible read-only
|
|
'' long tv_enable '0/non-0 = off/on write-only
|
|
'' long tv_pins '%pppmmmm = pin group, pin group mode write-only
|
|
'' long tv_mode '%tccip = tile,chroma,interlace,ntsc/pal write-only
|
|
'' long tv_screen 'pointer to screen (words) write-only
|
|
'' long tv_colors 'pointer to colors (longs) write-only
|
|
'' long tv_ht 'horizontal tiles write-only
|
|
'' long tv_vt 'vertical tiles write-only
|
|
'' long tv_hx 'horizontal tile expansion write-only
|
|
'' long tv_vx 'vertical tile expansion write-only
|
|
'' long tv_ho 'horizontal offset write-only
|
|
'' long tv_vo 'vertical offset write-only
|
|
'' long tv_broadcast 'broadcast frequency (Hz) write-only
|
|
'' long tv_auralcog 'aural fm cog write-only
|
|
''
|
|
''The preceding VAR section may be copied into your code.
|
|
''After setting variables, do start(@tv_status) to start driver.
|
|
''
|
|
''All parameters are reloaded each superframe, allowing you to make live
|
|
''changes. To minimize flicker, correlate changes with tv_status.
|
|
''
|
|
''Experimentation may be required to optimize some parameters.
|
|
''
|
|
''Parameter descriptions:
|
|
'' _________
|
|
'' tv_status
|
|
''
|
|
'' driver sets this to indicate status:
|
|
'' 0: driver disabled (tv_enable = 0 or CLKFREQ < requirement)
|
|
'' 1: currently outputting invisible sync data
|
|
'' 2: currently outputting visible screen data
|
|
'' _________
|
|
'' tv_enable
|
|
''
|
|
'' 0: disable (pins will be driven low, reduces power)
|
|
'' non-0: enable
|
|
'' _______
|
|
'' tv_pins
|
|
''
|
|
'' bits 6..4 select pin group:
|
|
'' %000: pins 7..0
|
|
'' %001: pins 15..8
|
|
'' %010: pins 23..16
|
|
'' %011: pins 31..24
|
|
'' %100: pins 39..32
|
|
'' %101: pins 47..40
|
|
'' %110: pins 55..48
|
|
'' %111: pins 63..56
|
|
''
|
|
'' bits 3..0 select pin group mode:
|
|
'' %0000: %0000_0111 - baseband
|
|
'' %0001: %0000_0111 - broadcast
|
|
'' %0010: %0000_1111 - baseband + chroma
|
|
'' %0011: %0000_1111 - broadcast + aural
|
|
'' %0100: %0111_0000 broadcast -
|
|
'' %0101: %0111_0000 baseband -
|
|
'' %0110: %1111_0000 broadcast + aural -
|
|
'' %0111: %1111_0000 baseband + chroma -
|
|
'' %1000: %0111_0111 broadcast baseband
|
|
'' %1001: %0111_0111 baseband broadcast
|
|
'' %1010: %0111_1111 broadcast baseband + chroma
|
|
'' %1011: %0111_1111 baseband broadcast + aural
|
|
'' %1100: %1111_0111 broadcast + aural baseband
|
|
'' %1101: %1111_0111 baseband + chroma broadcast
|
|
'' %1110: %1111_1111 broadcast + aural baseband + chroma
|
|
'' %1111: %1111_1111 baseband + chroma broadcast + aural
|
|
'' -----------------------------------------------------------
|
|
'' active pins top nibble bottom nibble
|
|
''
|
|
'' the baseband signal nibble is arranged as:
|
|
'' bit 3: chroma signal for s-video (attach via 560-ohm resistor)
|
|
'' bits 2..0: baseband video (sum 270/560/1100-ohm resistors to form 75-ohm 1V signal)
|
|
''
|
|
'' the broadcast signal nibble is arranged as:
|
|
'' bit 3: aural subcarrier (sum 560-ohm resistor into network below)
|
|
'' bits 2..0: visual carrier (sum 270/560/1100-ohm resistors to form 75-ohm 1V signal)
|
|
'' _______
|
|
'' tv_mode
|
|
''
|
|
'' bit 4 selects between 16x16 and 16x32 pixel tiles:
|
|
'' 0: 16x16 pixel tiles (tileheight = 16)
|
|
'' 1: 16x32 pixel tiles (tileheight = 32)
|
|
''
|
|
'' bit 3 controls chroma mixing into broadcast:
|
|
'' 0: mix chroma into broadcast (color)
|
|
'' 1: strip chroma from broadcast (black/white)
|
|
''
|
|
'' bit 2 controls chroma mixing into baseband:
|
|
'' 0: mix chroma into baseband (composite color)
|
|
'' 1: strip chroma from baseband (black/white or s-video)
|
|
''
|
|
'' bit 1 controls interlace:
|
|
'' 0: progressive scan (243 display lines for NTSC, 286 for PAL)
|
|
'' less flicker, good for motion
|
|
'' 1: interlaced scan (486 display lines for NTSC, 572 for PAL)
|
|
'' doubles the vertical display lines, good for text
|
|
''
|
|
'' bit 0 selects NTSC or PAL format
|
|
'' 0: NTSC
|
|
'' 3016 horizontal display ticks
|
|
'' 243 or 486 (interlaced) vertical display lines
|
|
'' CLKFREQ must be at least 14_318_180 (4 * 3_579_545 Hz)*
|
|
'' 1: PAL
|
|
'' 3692 horizontal display ticks
|
|
'' 286 or 572 (interlaced) vertical display lines
|
|
'' CLKFREQ must be at least 17_734_472 (4 * 4_433_618 Hz)*
|
|
''
|
|
'' * driver will disable itself while CLKFREQ is below requirement
|
|
'' _________
|
|
'' tv_screen
|
|
''
|
|
'' pointer to words which define screen contents (left-to-right, top-to-bottom)
|
|
'' number of words must be tv_ht * tv_vt
|
|
'' each word has two bitfields: a 6-bit colorset ptr and a 10-bit pixelgroup ptr
|
|
'' bits 15..10: select the colorset* for the associated pixel tile
|
|
'' bits 9..0: select the pixelgroup** address %ppppppppppcccc00 (p=address, c=0..15)
|
|
''
|
|
'' * colorsets are longs which each define four 8-bit colors
|
|
''
|
|
'' ** pixelgroups are <tileheight> longs which define (left-to-right, top-to-bottom) the 2-bit
|
|
'' (four color) pixels that make up a 16x16 or a 32x32 pixel tile
|
|
'' _________
|
|
'' tv_colors
|
|
''
|
|
'' pointer to longs which define colorsets
|
|
'' number of longs must be 1..64
|
|
'' each long has four 8-bit fields which define colors for 2-bit (four color) pixels
|
|
'' first long's bottom color is also used as the screen background color
|
|
'' 8-bit color fields are as follows:
|
|
'' bits 7..4: chroma data (0..15 = blue..green..red..)*
|
|
'' bit 3: controls chroma modulation (0=off, 1=on)
|
|
'' bits 2..0: 3-bit luminance level:
|
|
'' values 0..1: reserved for sync - don't use
|
|
'' values 2..7: valid luminance range, modulation adds/subtracts 1 (beware of 7)
|
|
'' value 0 may be modulated to produce a saturated color toggling between levels 1 and 7
|
|
''
|
|
'' * because of TV's limitations, it doesn't look good when chroma changes abruptly -
|
|
'' rather, use luminance - change chroma only against a black or white background for
|
|
'' best appearance
|
|
'' _____
|
|
'' tv_ht
|
|
''
|
|
'' horizontal number pixel tiles - must be at least 1
|
|
'' practical limit is 40 for NTSC, 50 for PAL
|
|
'' _____
|
|
'' tv_vt
|
|
''
|
|
'' vertical number of pixel tiles - must be at least 1
|
|
'' practical limit is 13 for NTSC, 15 for PAL (26/30 max for interlaced NTSC/PAL)
|
|
'' _____
|
|
'' tv_hx
|
|
''
|
|
'' horizontal tile expansion factor - must be at least 3 for NTSC, 4 for PAL
|
|
''
|
|
'' make sure 16 * tv_ht * tv_hx + ||tv_ho + 32 is less than the horizontal display ticks
|
|
'' _____
|
|
'' tv_vx
|
|
''
|
|
'' vertical tile expansion factor - must be at least 1
|
|
''
|
|
'' make sure <tileheight> * tv_vt * tv_vx + ||tv_vo + 1 is less than the display lines
|
|
'' _____
|
|
'' tv_ho
|
|
''
|
|
'' horizontal offset in ticks - pos/neg value (0 for centered image)
|
|
'' shifts the display right/left
|
|
'' _____
|
|
'' tv_vo
|
|
''
|
|
'' vertical offset in lines - pos/neg value (0 for centered image)
|
|
'' shifts the display up/down
|
|
'' ____________
|
|
'' tv_broadcast
|
|
''
|
|
'' broadcast frequency expressed in Hz (ie channel 2 is 55_250_000)
|
|
'' if 0, modulator is turned off - saves power
|
|
''
|
|
'' broadcasting requires CLKFREQ to be at least 16_000_000
|
|
'' while CLKFREQ is below 16_000_000, modulator will be turned off
|
|
'' ___________
|
|
'' tv_auralcog
|
|
''
|
|
'' selects cog to supply aural fm signal - 0..7
|
|
'' uses ctra pll output from selected cog
|
|
''
|
|
'' in NTSC, the offset frequency must be 4.5MHz and the max bandwidth +-25KHz
|
|
'' in PAL, the offset frequency and max bandwidth vary by PAL type
|
|
|
|
{{
|
|
|
|
┌──────────────────────────────────────────────────────────────────────────────────────────────────────────────────────────────┐
|
|
│ TERMS OF USE: MIT License │
|
|
├──────────────────────────────────────────────────────────────────────────────────────────────────────────────────────────────┤
|
|
│Permission is hereby granted, free of charge, to any person obtaining a copy of this software and associated documentation │
|
|
│files (the "Software"), to deal in the Software without restriction, including without limitation the rights to use, copy, │
|
|
│modify, merge, publish, distribute, sublicense, and/or sell copies of the Software, and to permit persons to whom the Software│
|
|
│is furnished to do so, subject to the following conditions: │
|
|
│ │
|
|
│The above copyright notice and this permission notice shall be included in all copies or substantial portions of the Software.│
|
|
│ │
|
|
│THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR IMPLIED, INCLUDING BUT NOT LIMITED TO THE │
|
|
│WARRANTIES OF MERCHANTABILITY, FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE AUTHORS OR │
|
|
│COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, │
|
|
│ARISING FROM, OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN THE SOFTWARE. │
|
|
└──────────────────────────────────────────────────────────────────────────────────────────────────────────────────────────────┘
|
|
}} |