noob: VGA ARGH!!!
cbmeeks
Posts: 634
Ok, maybe I have bitten off more than I can chew. But, I HAVE gotten a B/W NTSC video circuit to work before on a PIC.
Anyway, I am trying my luck at generating a VGA display using an SX28 and SX/B.
Here is my code:
Now, my monitor blinks orange when there is NO signal.
Using that code, the screen actually tries to lock on and I can "hear" it change. Then, the light stays a solid orange.
No green light which I am assuming means my timings are off.
Now, if I REMOVE the OPTION directive, the screen doesn't do anything but the light blinks from orange and green???
In this code, I am not trying to display anything...just simply trying to get a lock. The monitor is an old Samsung SyncMaster3 which I know works.
Any clues would help...
THANKS!
cbmeeks
Anyway, I am trying my luck at generating a VGA display using an SX28 and SX/B.
Here is my code:
' -------------------------------------------------------------------------
' Program Description
' -------------------------------------------------------------------------
'
' -------------------------------------------------------------------------
' Layout
' -------------------------------------------------------------------------
'
' RA.0 = Red0
' RA.1 = Red1
'
' RC.6 = HSync
' RC.7 = VSync
' -------------------------------------------------------------------------
' Device Settings
' -------------------------------------------------------------------------
DEVICE SX28, OSCHS2, TURBO, STACKX, OPTIONX
FREQ 50_000_000
' -------------------------------------------------------------------------
' Variables
' -------------------------------------------------------------------------
VSync var rc.7
HSync var rc.6
' -------------------------------------------------------------------------
INTERRUPT
' -------------------------------------------------------------------------
'Vertical Timing
'Horizonal Dots 640 640 640
'Vertical Scan Lines 350 400 480
'Vert. Sync Polarity NEG POS NEG
'Vertical Frequency 70Hz 70Hz 60Hz
'O (ms) 14.27 14.27 16.68 Total frame time
'P (ms) 0.06 0.06 0.06 Sync length
'Q (ms) 1.88 1.08 1.02 Back porch
'R (ms) 11.13 12.72 15.25 Active video time
'S (ms) 1.2 0.41 0.35 Front porch
' ______________________ ________
'________| VIDEO |________| VIDEO (next frame)
' |-Q-|----------R-----------|-S-|
'__ ______________________________ ___________
' |_| |_|
' |P|
' |---------------O----------------|
low VSync 'P
pauseus 60
low VSync 'Q
pauseus 1020
high VSync 'R
pauseus 15250
low VSync 'S
pauseus 350
high VSync
RETURNINT
' =========================================================================
PROGRAM Start
' =========================================================================
Start:
output ra.0
output ra.1
output rc.6
output rc.7
OPTION = $88 ' interrupt, no prescaler
Main:
'Horizonal Dots 640 640 640
'Vertical Scan Lines 350 400 480
'Horiz. Sync Polarity POS NEG NEG
'A (us) 31.77 31.77 31.77 Scanline time
'B (us) 3.77 3.77 3.77 Sync pulse lenght
'C (us) 1.89 1.89 1.89 Back porch
'D (us) 25.17 25.17 25.17 Active video time
'E (us) 0.94 0.94 0.94 Front porch
' ______________________ ________
'________| VIDEO |________| VIDEO (next line)
' |-C-|----------D-----------|-E-|
'__ ______________________________ ___________
' |_| |_|
' |B|
' |---------------A----------------|
low HSync 'B
pauseus 4
low HSync 'C
pauseus 2
high HSync 'D
pauseus 25
low HSync 'E
pauseus 1
GOTO Main
Now, my monitor blinks orange when there is NO signal.
Using that code, the screen actually tries to lock on and I can "hear" it change. Then, the light stays a solid orange.
No green light which I am assuming means my timings are off.
Now, if I REMOVE the OPTION directive, the screen doesn't do anything but the light blinks from orange and green???
In this code, I am not trying to display anything...just simply trying to get a lock. The monitor is an old Samsung SyncMaster3 which I know works.
Any clues would help...
THANKS!
cbmeeks
Comments
Why are your changing HSync in the main code and VSync in the interrupt ?
I haven't actually connect to the montor yet, I'm trying to find a cheap one incase I destroy it [noparse];)[/noparse]
Bean.
▔▔▔▔▔▔▔▔▔▔▔▔▔▔▔▔▔▔▔▔▔▔▔▔
"SX-Video·Module" Now available from Parallax for only $28.95
http://www.parallax.com/detail.asp?product_id=30012
Product web site: www.sxvm.com
"If you keep doing what you always did, you'll keep getting what you always got."
·
lol...yeah, I think we are the only two...hehe
Why? I don't know why. All I can find is timing information but I can seem to find anything that says when to start the timing, etc.
So, I am experimenting I guess.
I thought the VSync and HSync had to happen at the same time....hmmm
Back to the drawing board.
cbmeeks
BTW: I just got my video overlay to work, finally...
Bean.
▔▔▔▔▔▔▔▔▔▔▔▔▔▔▔▔▔▔▔▔▔▔▔▔
"SX-Video·Module" Now available from Parallax for only $28.95
http://www.parallax.com/detail.asp?product_id=30012
Product web site: www.sxvm.com
"If you keep doing what you always did, you'll keep getting what you always got."
·
congrats on your video overlay