I couldn't find the binary value in instructions.spin for JMP, there's JMPRET but no JMP as I was going to do it as a single int, included in the C. I ended up using a 2K pre-cleared buffer ( part of the screen ), so it'll be nops, until it gets to the sysvars I'll fix it in next update.
HAHA nice one on licensing!
Works a treat now anyway, even with the 0s for the coginit.
Will fire up the PC later, and do a jmp #$
Updated the first post enjoy!
JMP and JMPRET have the same opcode. JMPRET writes its result but JMP doesn't.
This version appears to work very well on directories and files.
Can somebody tell me the proper way to compare video signal levels, and the differences between say the output of a home DVD player and the FPGA emulation?
I've been trying to resolve the component video tearing issues, and I'm confused about the levels I'm seeing on my scope.
Should I take a measurement while connected to a display, or not, and or across a specific load?
Secondly, how do we calculate an output level from the DACS when being driven by the video generator?
I'm convinced the component video levels are wrong, which results in the tearing. On this version, in text mode, I get tearing on some displays, and only for frame 1, but not on others... Weird. Kind of want to nail this down now, so we've got a very solid, general purpose "world" TV driver.
**I didn't think the buttons worked on this FPGA image! Now I gotta go back and make the fractal interactive.
This version appears to work very well on directories and files.
Can somebody tell me the proper way to compare video signal levels, and the differences between say the output of a home DVD player and the FPGA emulation?
I've been trying to resolve the component video tearing issues, and I'm confused about the levels I'm seeing on my scope.
Should I take a measurement while connected to a display, or not, and or across a specific load?
Secondly, how do we calculate an output level from the DACS when being driven by the video generator?
I'm convinced the component video levels are wrong, which results in the tearing. On this version, in text mode, I get tearing on some displays, and only for frame 1, but not on others... Weird. Kind of want to nail this down now, so we've got a very solid, general purpose "world" TV driver.
**I didn't think the buttons worked on this FPGA image! Now I gotta go back and make the fractal interactive.
Cheers potato head
I'm not sure on how to calculate the levels from the DACS, but I'm sure there's gotta be someone here who would know!
As you say it would be nice to nail it now, so we've got a very solid general purpose "world" TV driver as you put it
I'll get on making the Width and Height selectable real time ( during vblank ) also next.
The DACs on the DE0-Nano and DE2-115 boards are 47 ohms, while the actual chip DACs are going to be 75 ohms. This could be simulated on the DE0/DE2 boards by inserting a 28-ohm series resistor in the DAC output paths.
Thanks Chip. Any chance you could post up a run through of how you calculate a value, say one of the sync levels. I made a cable that lets me measure a home DVD player under load. Things make much more sense now! Hope that's the right answer.
...
I've been trying to resolve the component video tearing issues, and I'm confused about the levels I'm seeing on my scope.
Should I take a measurement while connected to a display, or not, and or across a specific load?
...
I'm convinced the component video levels are wrong, which results in the tearing. On this version, in text mode, I get tearing on some displays, and only for frame 1, but not on others... Weird. Kind of want to nail this down now, so we've got a very solid, general purpose "world" TV driver.
Measurements should always be with load.
Tearing is usually a sync issue, not so much a video level, but high video drive can shift slicing levels slightly.
If it is frame-related (top of screen only) then the frame sync pre/post 2f generation may need work.
Create a test pattern with low video brightness levels, and check for sync stability, then increase brightness.
Thanks Chip. Any chance you could post up a run through of how you calculate a value, say one of the sync levels. I made a cable that lets me measure a home DVD player under load. Things make much more sense now! Hope that's the right answer.
You can adjust the output level of the DACs with the s constant at begin of the CON section.
This s value scales the Y,I,Q coefficients, which actually set the DAC output scaling (255 = 3.3V).
potatohead, give the s constant a go, see if it's that, but I'm tempted to go with jmg, as slight skewing can usually be caused by timing of syncs not being spot on. So can you give that a look on the scope also?
Yes, I am setup for another round of test, measure, tweak. Love the driver on SD card. It helps as I'm on the Mac for a while longer. I have an old analog business graphics NTSC display that will render most PAL correctly, but it's monochrome. A SONY CRT, which is really upset with the component video, normal 80's era TV, and two HD digital sets.
Has anybody tested PAL component? Does it display correctly? I really can't do this as my PAL capture card does too much correction, and so far has rendered every version of this driver correctly, and it has no component to even try.
I'll be focusing on NTSC composite, which tears in text mode, though it appears to display pretty well in graphics mode, and component outputs.
That's what I'm wondering. I don't think it's the displays because all the analog ones act wonky, and they render everything else just fine. Could be the FPGA... doubt it, and I'm running plain vanilla, just the breakout board and ordinary cable.
jazzed are you talking flickering in portions of the pictures, or dot crawl? and are you seeing it in the latest driver? and is it regular or once in a while?
Comments
Can somebody tell me the proper way to compare video signal levels, and the differences between say the output of a home DVD player and the FPGA emulation?
I've been trying to resolve the component video tearing issues, and I'm confused about the levels I'm seeing on my scope.
Should I take a measurement while connected to a display, or not, and or across a specific load?
Secondly, how do we calculate an output level from the DACS when being driven by the video generator?
I'm convinced the component video levels are wrong, which results in the tearing. On this version, in text mode, I get tearing on some displays, and only for frame 1, but not on others... Weird. Kind of want to nail this down now, so we've got a very solid, general purpose "world" TV driver.
**I didn't think the buttons worked on this FPGA image! Now I gotta go back and make the fractal interactive.
Cheers potato head
I'm not sure on how to calculate the levels from the DACS, but I'm sure there's gotta be someone here who would know!
As you say it would be nice to nail it now, so we've got a very solid general purpose "world" TV driver as you put it
I'll get on making the Width and Height selectable real time ( during vblank ) also next.
Measurements should always be with load.
Tearing is usually a sync issue, not so much a video level, but high video drive can shift slicing levels slightly.
If it is frame-related (top of screen only) then the frame sync pre/post 2f generation may need work.
Create a test pattern with low video brightness levels, and check for sync stability, then increase brightness.
You can adjust the output level of the DACs with the s constant at begin of the CON section.
This s value scales the Y,I,Q coefficients, which actually set the DAC output scaling (255 = 3.3V).
Andy
potatohead, give the s constant a go, see if it's that, but I'm tempted to go with jmg, as slight skewing can usually be caused by timing of syncs not being spot on. So can you give that a look on the scope also?
Yes, I am setup for another round of test, measure, tweak. Love the driver on SD card. It helps as I'm on the Mac for a while longer. I have an old analog business graphics NTSC display that will render most PAL correctly, but it's monochrome. A SONY CRT, which is really upset with the component video, normal 80's era TV, and two HD digital sets.
Has anybody tested PAL component? Does it display correctly? I really can't do this as my PAL capture card does too much correction, and so far has rendered every version of this driver correctly, and it has no component to even try.
I'll be focusing on NTSC composite, which tears in text mode, though it appears to display pretty well in graphics mode, and component outputs.
Maybe others can chime in.