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Controlling a DLP projector DMD chip directly from the Pi!!!

Posted: Thu Mar 05, 2015 10:58 pm
by hradec
Hi there!!

I'm trying to build an interface board to power up and control an TI DLP Lightengine directly from the Pi. Essentially, I want to control the DMD Micromirror array directly (the DLP DMD Chip - http://www.ti.com/lit/ds/symlink/dlp4500.pdf) to generate images, without using the control chip from TI (the DLPC6401 control chip - http://www.ti.com/lit/ds/symlink/dlpc6401.pdf), which seems to me a way more complicated chip to design a board to, waaaaaay above my level!!

Although the DLPC6401 controller chip has a nice i2c interface and all, I don't even known were to start to build a protoboard for it.

So, I'm choosing the path of using the rPI directly as the controller chip, which would also make the whole interface way cheaper.

As my electronic knowledge is essentially hobbyist, I'm having a bit of a hard time to get the barebones of a prototype PCB that would connect the DLP Lightengine connector (AXT580124 - http://www3.panasonic.biz/ac/e_download ... ng_f4s.pdf) to a couple of MCP23017 chips, so I can access all the 24 data ports, plus the other 8 control/reset ports to start "hacking/trial and error" learning on how to control the DMD chip device.

Apart from that, I also need to supply all the necessary voltages (VCC –0.5-4V, VREF –0.5-4V, VOFFSET –0.50-8.75V, VBIAS –0.5,17.0V, VRESET –11,0.5V) properly, and last, power up all the 3 RGB high power LEDs!

My initial challenge here has being to figure how to sold the AXT580124 connector to a protoboard of some sort, so I can start prototyping the connections to the MCP23017 chips and voltages.

Does anybody knowns if Is there any protoboard that would accomodate the AXT580124 80 pins connector (0.15mm terminals with 0.40mm of space in between)?

Or do I have to build one from scratch just for that connector?

make sense??

cheers...
Hradec

PS: For the curious, the idea is, essentially, to turn the rPi into a smart DLP projector, to be used in 3d printers, scanners or anything else you think about it!!

Re: Controlling a DLP projector DMD chip directly from the P

Posted: Sat Mar 07, 2015 4:56 pm
by rotwang
Look at page 19 of the TI datasheet, the fact that timings are in nano-seconds should warn you that you don't have a hope in hell of generating the timing from a raspberry pi. A very fast FPGA maybe, if you're very good with Verilog.

Re: Controlling a DLP projector DMD chip directly from the P

Posted: Sun Mar 08, 2015 6:35 am
by hradec
rotwang wrote:Look at page 19 of the TI datasheet, the fact that timings are in nano-seconds should warn you that you don't have a hope in hell of generating the timing from a raspberry pi. A very fast FPGA maybe, if you're very good with Verilog.
In page 19, they specify the max DCLCK cycle as 12.5ns, which reflects a clock of 80mhz.

According to this post (http://www.raspberrypi.org/forums/viewt ... p?p=275973), its possible to generate such clock from the rPi, so I thought it would be ok.

SAC_CLCK min cycle seems to also be 12.5ns, so I'm hopping to use the same one for booth.

I also want to try slower clocks (cycles bigger than 12.5ns) to see if it can work... Maybe it does... although out of spec, it may be possible to drive the micromirrors at lower speed.

I still need to learn how the DDR specs are and also how the LVCMOS protocol works to send the dmd data through.

But even if I cant get all the data transfer speed the chip can do, I would be pretty happy to generate one image per second or even less!!

For 3d print and 3d scanning, thats more than enough!

An DLP light engine costs around U$250 bucks, wich is way cheaper than a full blow dlp projector!

Re: Controlling a DLP projector DMD chip directly from the P

Posted: Sun Mar 08, 2015 4:24 pm
by mikronauts
The only way it barely might be possible to drive the panel is if you use all the pins and can drive the DLP as if it was an LCD panel - even then I really doubt it.

Being able to generate an 80MHz clock on a pin (which I also have reservations about) does not equate to being able to drive a large number of data onto other GPIO pins at the same clock rate.

Re: Controlling a DLP projector DMD chip directly from the P

Posted: Mon Dec 21, 2015 7:48 pm
by Rocket0984
Hey, any update on this project? I too am building a dmd projector, but I'm using an fpga to control it. It's WAY beyond my league too.

Re: Controlling a DLP projector DMD chip directly from the P

Posted: Sat May 14, 2016 5:09 am
by hradec
unfortunately not...

I don't have the expertise to design the required 3 different types of power supply. The connector also was a problem considering it has 80 pins, it would require a bunch of layers to design the pcb.

have you managed to do that??

Re: Controlling a DLP projector DMD chip directly from the Pi!!!

Posted: Wed Feb 21, 2018 3:55 am
by Shellhead
Hey has anybody attempted to interface with one of these dmd chips? I'm wanting to interface with it to my lattice ice via custom pcb. Wanting to play with it for SLA Printing / circuit board etching. Any one go down this road??

Re: Controlling a DLP projector DMD chip directly from the Pi!!!

Posted: Thu Feb 22, 2018 7:36 pm
by hradec
no success... I've tried a lot but never got it to work... :(