04 MFD Resolutions/Timings

Specifically I want to know what the Nav unit would be putting out to it normally. I've got a VGA interface wired up and am using powerstrip to calibrate the picture - I got it almost perfect today at about 15.xx Hz horizontal timing, but I'm not sure what resolution I should be setting it to so I'm outputing "native" - or what the Nav is. Help?

 

I've already had some success. What I did was create a VGA adaptor to the RGBS signals and connected the Sync to the Horizontal Sync from the RGBS. I then used Powerstrip to tune the picture. My best result was setting 640x480 as the resolution and then setting horizontal sync to close to 15.75 kHz. The result was a very clear image, though there was a bit of flickering when I moved the mouse cursor on it. Hence why I wanted to know what the native res was - I'll update this thread when I try that.

 

At the time I was using a Toshiba M200 Tablet PC (my brother's - it was on hand). I think it worked because it has to basically swap horizontal and vertical sync when you put it in Tablet mode.

I don't know whether it's strictly necessary to combine horizontal and vertical sync's for the MFD - if you supply only one then ensure the output signal is 60 Hz compatible then I think it still works. Alternatively the horizontal sync I picked just happened to look like the appropriate composite sync.

I'll update you guys with some more once I get my mini-ITX system installed and running - that's going to be the actual in car PC so I'll be a bit for tenacious in getting it tuned to the MFD.

 

The signal to the screen is definitely interlaced, but from what I can tell the input circuitry accepts 640x480 (i.e. NTSC) rather then anything like the native resolution. My success with getting a picture seems to have been due to me tuning the horizontal timing so that the vertical timing was implicitly obtained - which works but is not stable. Phase II then - building a circuit to combine the sync's.

 

UPDATE: Haver just finished building the component sync signal combiner someone linked to above. I have a conundrum however - which lines should I connect to the ground in the circuit?

The Prius has 5 wires - R,G,B,Sync,Ground. Currently I've connected the video return lines to the ground on the Prius and the circuit. I'm wondering if I should also connect the "Sync Return" on the VGA connector to the Prius and circuit ground?

I would figure this out myself, but I don't have ready access to a 'scope (looking into it though).

 

That's what I ended up doing and it turned out very well, I can set a laptop to output an NTSC signal and with a minor tweak to the front porch width of the sync it lines up beautifully with the screen (except for some minor flicker but I think it's because I didn't stabilize the +5V in my circuit with enough capacitance [or indeed any]).

 

I using the Nav connector as my input. I cut the main harness and put a VGA connector and a DB9 connector for video and AVC-LAN respectively. I wouldn't recommend doing what I've done just yet though since I've now got what I'm hoping is the TSB EL002-05 problem with my MFD intermittently.

Does anyone know what would happen if the IEBus lines were somehow shorting together without being properly terminated? Would it bring down the whole bus? I don't think that's what's happening but it's been very hot recently and some of my heatshrink has continued to shrink. I'm going to wrap everything up in electrical tape tonight and see if it makes a difference.

 

I've guessed that much (since the whole thing comes back up every now and again) but I'm at a loss to explain where it's being shorted. I went through and put electrical tape over all my heat shrink contacts but I'm still getting the problem. Which is a pain in the nice person because it MIGHT be an actual MFD problem a lot of people have experienced or it could be my mod. I just don't want Toyota replacing the MFD and then finding out there was a short I hadn't accounted for (since I'd have to pay for the MFD then).

I might have to pull the back of it apart and unplug the Nav system there to see if the problem still arises (since that's the only cable I've actually changed).

 

If you're already doing the appropriate H+V -> Composite Sync conversion then what you have to do in powerstrip is, if I recall (been programming my IEBus translater for a while) is tweak the front and back porch of the sync signals. I found I needed to push the front porch up one unit. Once you do that the signal locks solid on the screen.