I have an MST8131B here on a 17" viewsonic panel.

According to the datasheet for the MST chip there is a register that needs to be set to allow non-scaling modes, it supports the feature in the registers:
Click to view attachment

I am thinking that just flipping the Scaling bit on Vertical to OFF would suffice to make everything the right aspect ratio. I would still have a problem with lower resolution sources than 1280x720p, or 4:3 aspect ratios, but I could live with it because most of my stuff will make 720p.

I am a little new to the appliance hacking business.

Does anyone know how to get the register bit set? Options I can see right now are modifying the Firmware, which would require a eeprom reader/writer, or communicating over the Serial communications bus.

I would probably buy an EEPROM Reader/writer if I knew this worked by setting it from the Serial command bus.

Problems I could foresee would be the firmware written so I can't set it, or the necessity of setting the bit over the serial bus every time.

I need a 720p native resolution, and the datasheet for every display I can find doesn't list 720p unscaled modes. "Native 720p is a misnomer because 768 is not 720p native. I could live with it if there was some truth to the advertising, maybe a tagline like: "720p capable in theory, but we turn the scaler on and make all your stuff look worse and out of aspect for no good reason"

So I am resorting to hacking the firmware/scaling-input chip on this board. It is a Viewsonic VX715, and it lists 1280x720p clearly in the manual as a resolution, but it is still scaled .

I may have seen a guide to hacking LCD firmware here, or one enabling test patterns via the serial bus, if anyone knows of one, could they please point me to it?

nubie, I'm not an expert about hacking/reprogramming chips or anything, but I'd be careful here. A lot of times they may have the index of the register that you need to modify, but that may end up being an index offset from some section of memory (ROM I guess here) that is set aside for the SFRs.

I would supposed the easiest way to reprogram the chip would be to use your eeprom reader/writer method and just change the corresponding bit(s) then reprogram. But be sure to make a copy of the binary image you pull off it in case it's unsuccessful, it would suck to end up with a bum LCD. Let us know how this goes for you, it might be valuable to many of us.