RE: [beagleboard] Re: DVI-D to LCD panel conversion

I’m quite fortunate that I am currently working with the Mistral EVM board, but for us, the need to add the LVDS support for the larger LCD panels is something we are having to work on… a custom board to expand isn’t something that can be constructed in a day…

perhaps one option would be that a REV C/D beagle board could have the extra circuit and board space (?) the the buffer translator and LVDS driver IC’s but not actually populate them as the ‘standard’ beagle production. It can then be up to the hobbyist to get their soldering iron out and add them :slight_smile: Or a different assembly run at the Beagle assembly house to provide that variant.

That is certainly something we are looking at doing with our intended product with a custom controller board utilising the OMAP.


PS. a ‘proper’ type A USB host connector too… I am still struggling to source a suitable cable/adapter here in the UK to allow me to plug something usable in to the OTG port on the EVM :frowning:

Rev C will most defintely not have this feature added. This I can promise. It may be an option for a later revsion as I have already mentioned. The option that Jason mentioned is a viable option for now. It supports TTL and LVDS outputs an dis availble today.


I second this approach. The thought of converting parallel LCD
signals into DVI, then DVI into LVDS or back to VGA (ew) isn't quite
as much fun -- and is bad for size, power consumption, wallet, etc.

Something I have been considering with the current B4 board is to
remove the DVI serialiser and use its pads (or the smaller resistor
packs further up the tracks) to drive an LVDS serialiser (or buffers
up to 3.3V to drive a parallelly TFT panel). It strikes me that the
simple addition of some extra (larger) pads to access the 24bit LCD
data may be useful in expanding the possibilities for some people,
maintaining the hobbyist hacking element and doing so with $0 extra
cost? Maybe just space for a second expansion header, without
footprinting actual LVDS serialisers/buffers/etc.

For instance- disable the onboard DVI serialiser (GPIO -> off) and a
little mezzanine card driving your LVDS TFT can do all the work. Or,
a different mezzanine card just voltage buffering to a parallel TFT
panel (e.g. Sony PSP panel). Or, the crazy could use a makeshift
(R2R) DAC and drive analogue RGB video from the same pins. :wink:

Pads would at least give more people the option of playing about and
seeing what they can add on, I think.



You have some interesting ideas, however, on the rev B boards we are already in full production, so scrapping 1500 boards will have a heavy cost impact to say the least and the Rev C board is already in proto stage. I don’t think we will have time to fit the pads in without affecting the overall layout and thereby forcing a second proto stage. We don’t want to order a bunch of Rev B board for the next build and instead move to Rev C. Any delays at this time in Rev C will force us to do just that, thereby delaying Rev C even further.

We are looking to add this capability in later version of the board, but that will be sometime next year.



Are there any guidelines for installing/soldering pins for expansion header?

Drill size, wire dia for pins etc,

Are these functionally ready for business?


John W.

They are just standard solder in .1 x .1 strip headers. You can use single or dual row headers. These are made by many suppliers. They are actually the same as the ones used on the JTAG and Serial header. You can get the base part number for these off of the BOM.

The only guideline is your standard soldering practices. You can use lead-free or lead based solder. Just be careful not to get solder splashes on the board. The drill size information is contained in the Gerber or PCB files.

Yes these are functionally ready for business. Please keep in mind that they are 1.8V signals and if you expose them to anything higher, you will damage the board. Make sure you do not exceed the current ratings on the rails as specified in the HW Reference Manual.


One problem I ran into is that I want to use a ribbon cable to connect
the Beagle to an FPGA board, but they do not seem to make 28 pin
ribbon cable connectors.


You can just offset it to where some is left over. A 30 or 34 pin dual row should work. You can also fill the unused holes with epoxy to plug then so that you don’t get off on the connections when pluggin in and unplugging the cable.