TV problem
Lee Marshall
Posts: 106
I am now trying to run the tv text demo, but all i get is that black/white dot pattern like when you are tuning to an off-air signal.(except when the prop is off/booting, then i just get black)
i am using an RCA jack, plugged into my TVs composite input with the DAC provided in the prop manual except im using pins 16 and upwards rather than 12 upwards.
I am now using a 4 mhz SMD oscillator, my scope says it is producing a stable square wave.
here is my TV_Text_Demo.spin(exactly the same except for clock settings and the start pin)
also, at the bottom of TV_Text.spin, i have changed the LSB of mode from 0 to 1(for PAL):
Is there some setting i havent changed for PAL?
Can anyone help with this?
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Holy parallel processing, Batman!
Post Edited (Mr Crowley) : 10/6/2007 4:24:34 PM GMT
i am using an RCA jack, plugged into my TVs composite input with the DAC provided in the prop manual except im using pins 16 and upwards rather than 12 upwards.
I am now using a 4 mhz SMD oscillator, my scope says it is producing a stable square wave.
here is my TV_Text_Demo.spin(exactly the same except for clock settings and the start pin)
CON
_clkmode = XINPUT + PLL16X
_xinfreq = 4_000_000
OBJ
text : "tv_text"
PUB start | i
'start term
text.start(16)
text.str(string(13," TV Text Demo...",13,13,$C,5," OBJ and VAR require only 2.8KB ",$C,1))
repeat 14
text.out(" ")
repeat i from $0E to $FF
text.out(i)
text.str(string($C,6," Uses internal ROM font ",$C,2))
repeat
text.str(string($A,16,$B,12))
text.hex(i++, 8)
also, at the bottom of TV_Text.spin, i have changed the LSB of mode from 0 to 1(for PAL):
tv_params long 0 'status
long 1 'enable
long 0 'pins
long %10011 'mode
long 0 'screen
long 0 'colors
long cols 'hc
long rows 'vc
long 4 'hx
long 1 'vx
long 0 'ho
long 0 'vo
long 0 'broadcast
long 0 'auralcog
Is there some setting i havent changed for PAL?
Can anyone help with this?
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Holy parallel processing, Batman!
Post Edited (Mr Crowley) : 10/6/2007 4:24:34 PM GMT
Comments
I used 5MHz and pins 12-16. perhaps the Start(pin) method of TV_Text doesn't set the pin grouping to select the lower four pin group ? You could have a peek into TV_Text.spin to check that ( or even force the 'pins' value to what it should be within Start ). TV.spin describes the 'pins' bit-mask values.
If you don't get anywhere it may be worth going to 5MHz, pins 12-16 to ensure everything is working, then make the change to what you actually want one step at a time.
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Holy parallel processing, Batman!
That's why I asked whether MPE_TEXT would run... It displays in both mode as a demo....
my new code is now misbehaving.
Its meant to output characters from a keyboard to a TV,
I get the:
Keyboard Interface
Please Connect a keyboard
Keyboard Connected
but as soon as i press a key, the screen blanks.
CON _CLKMODE = XINPUT + PLL16X _XINFREQ = 4_000_000 OBJ Term : "tv_terminal" KB : "Keyboard" VAR Byte KeyCode PUB Main Term.Start(16) KB.start(26,27) Term.str(string("Keyboard Interface")) Term.out(13) if not KB.Present Term.str(string("Please connect a keyboard")) Term.out(13) repeat until KB.Present Term.str(string("Keyboard Connected")) Term.out(13) repeat repeat KeyCode := KB.key until KB.Key Term.out(KeyCode)Also: hippy, i cant see a parameter called rows, but there is a vx.(is changing this stuff to stop the tv from displaying everything squished?)
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Holy parallel processing, Batman!
Post Edited (Mr Crowley) : 10/6/2007 7:25:39 PM GMT
Also: Better write "UNTIL KeyCode" rather than "UNTIL KB.key"
0 is called "home" but in fact CLEARS the screen.
While you wait for a character, zeroes are stored into keyCode.
As soon as the first non-zero key is detected the loop breaks, but keycode still contains zero...
So just follow my second advice, and the first one will be obsolete
I actually meant that to be keycode, i not sure how it ended up the other way.
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Holy parallel processing, Batman!
what exactly can it do when in composite mode? can it produce the color burst at the horizontal blanking interval, can it produce the sync pulses??? what does it do about vertical sync?
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Holy parallel processing, Batman!
pppppppppp is ten bits from 6..15, right?
but it says p is from bits 0..9.
cccc00 is six bits(whats with the 0s) from 0..5?
it says c is from 10..15
so, what is the real structure of the tv_screen word?
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Holy parallel processing, Batman!
(a) You have the contents of the tv_screen which should better had been called tv_tiles... But it's too late now..
It contains a COLOR NUMBER 0 to 63 in its upper 6 bits and a TILE NUMBER in its lower 10 bits.
(b) The last two lines in the text you copied explain how this TILE NUMBER corresponds to a HUB address:
When multiplied with 64 it points to a 16x16 tile, consisting of 16 LONGS each of them containing 16 pixels of 2 bits each for the four-color mode shift-out
Hope this helped.
Post Edited (deSilva) : 10/7/2007 10:21:59 PM GMT
It took me while to get my head around that description. The bottom 10 bits 'pppppppppp' of screen[noparse]/noparse are used as the top 10 bits of the address the tile to display starts at. The character code value ( to select a particular tile ) is then added ( Or'd ) to that address, the tile is then a set of longs from that address.
I know I've ducked "why are there just four bits for the character code 'cccc' , 16 characters". I'm not sure. The Spin method "PRI print(c)" where screen[noparse]/noparse is set shows how the pointer to the tile is setup. In a recent post I included details of how to switch TV_Text to using user defined characters. That will show how I did it there and may provide a little help and clarity.
http://forums.parallax.com/forums/default.aspx?f=25&m=219325