I've seem some Asian small monitors supply a VGA-Mini-USB wiring adapter cable, ...
Expanding on this cable/Connector alternatives, just spotted this topical info over in AVR freaks
["Congratulations! You have discovered a VGA/RGB sync mode that's been in existence for only about 35 years. It's called "Digital Composite Sync", "DCS", or "4-wire RGB".
The "Sync-On-Green" Bob Gardner refers to is also known as "3-wire Sync" or simply "SOG". In this method the sync pulse is "attached" to the bottom of the green signal of the R-G-B triad of data lines. Logically, this sync is the same as "DCS" described above. That is, it is a composite of horizontal and vertical sync pulses passed over one signal path, rather than two as with the more common 5-wire RGB type. (Also know as "Digital Separate Sync" or "DSS".)
DCS is formed by ORing the H-Sync and V-sync together. However, I don't exactly recall if the Inclusive or the Exclusive OR function is used to perform this combining.
The majority of existing VGA monitors can handle 5-wire and 4-wire sync types. A smaller number can handle Sync-On-Green signals."]
ie, they are saying a single sync line (H) is fine - that can make a mini/micro USB more viable, as the outer case is not needed at all.
Just needs a supply of cheap HD15_VGA-Mini-USB cables ?
Yep, sync on green is a nice option. Not all VGA devices will support it. That does bring VGA much closer to component video in terms of conductors. Still, component has the very nice quality of only requiring one pin for monochrome video, and it works all the way down to TV SD sync rates.
Yep, sync on green is a nice option. Not all VGA devices will support it.
My focus was on "4-wire RGB", using a single (H) wire, but maybe I did not make that very clear.
As you say, and the poster also said, SOG is not universal, but it seems "4-wire RGB" is.
And the 4 wire RGB is a lot more common. I don't know whether or not it's universal. The FPGA emulation has four DACS. Perhaps that is what it used? I should go and look, but I'm not where I can do that.
It'd be relatively easy to whip up a test 4 wire program to suit the P1 wouldn't it? Then we can crowdsource test and see what monitors won't accept it.
Perhaps put together a 'slide show' of vga entries in your competition to keep it interesting, and use propellent batch file or something to load each in turn?
Just out of curiosity, are the guys who are wanting to still use Composite with the new chip, would component work? as that would be a little easier where the dacs are concerned.
Component would be easier, but ultimately I need a single wire signal. External passive combination of Y-C (s-video) would be fine though. Or at worst, I could work with just greyscale luminance, while we wait to see what Chip has in mind.
Comments
Expanding on this cable/Connector alternatives, just spotted this topical info over in AVR freaks
["Congratulations! You have discovered a VGA/RGB sync mode that's been in existence for only about 35 years. It's called "Digital Composite Sync", "DCS", or "4-wire RGB".
The "Sync-On-Green" Bob Gardner refers to is also known as "3-wire Sync" or simply "SOG". In this method the sync pulse is "attached" to the bottom of the green signal of the R-G-B triad of data lines. Logically, this sync is the same as "DCS" described above. That is, it is a composite of horizontal and vertical sync pulses passed over one signal path, rather than two as with the more common 5-wire RGB type. (Also know as "Digital Separate Sync" or "DSS".)
DCS is formed by ORing the H-Sync and V-sync together. However, I don't exactly recall if the Inclusive or the Exclusive OR function is used to perform this combining.
The majority of existing VGA monitors can handle 5-wire and 4-wire sync types. A smaller number can handle Sync-On-Green signals."]
ie, they are saying a single sync line (H) is fine - that can make a mini/micro USB more viable, as the outer case is not needed at all.
Just needs a supply of cheap HD15_VGA-Mini-USB cables ?
I guess the main benefit would be the space and cost savings.
Wonder whether we could come up with a resistor arrangement that could do both vga or usb
Nice that they are exploring it though.
My focus was on "4-wire RGB", using a single (H) wire, but maybe I did not make that very clear.
As you say, and the poster also said, SOG is not universal, but it seems "4-wire RGB" is.
And the 4 wire RGB is a lot more common. I don't know whether or not it's universal. The FPGA emulation has four DACS. Perhaps that is what it used? I should go and look, but I'm not where I can do that.
Perhaps put together a 'slide show' of vga entries in your competition to keep it interesting, and use propellent batch file or something to load each in turn?