pieroc91
Posts: 3
Joined: Fri Jun 29, 2018 2:08 pm

Raspberry and a vintage video ADC

Wed Jul 11, 2018 6:49 pm

Hi everybody, i'm new to the forum and looking forward to choose the right hardware for this project.

I've got a Kodak DCS100, the very first digital camera that went to the market, it is a massive device built around a Nikon F3 with military degree materials, a 1.3ccd sensor, linear regulators, 8bit video a/d and a Altera EP910 for controlling things.

The bad thing is that the storage unit (a massive thing with lots of microcontrollers, a lead acid battery, regulators, a SCSI hard drive, an LCD panel and controls) is missing.

So, luckily there are schematics and original source code online, also i've contacted the designer of the camera itself who gave me extra info on how interface what i got and end with a usable camera.

i'm planning on replacing all the storage unit with a raspberry, and LCD panel, and some li-ion batterys.

What i wanted to know is that the Raspberry is capable of handling the signals from the camera.

The camera receives and sends very simple parallel 8bits latched registers in a db15 port for commands, this is the easy part.

On the hard part, the Raspberry must read the 8bit A/D data to make the picture that is output on the same pins that the camera send and receives commands, also the camera while is turned on is generating a 6mhz clock signal that syncs the video output, also is necesary to write precisely the init procedures in order to sync the horizontal and vertical sync.

Well thats quite a lot for a start post, hope someone can help me

Thanks a lot!

KnarfB
Posts: 194
Joined: Wed Dec 14, 2016 10:47 am
Location: Germany

Re: Raspberry and a vintage video ADC

Mon Jul 16, 2018 4:58 am

Hi pieroc91,

wow, you got a great piece of hardware.

Did I get it right: The Raspi needs to read a 8-bit ADC data stream with an externeal 6 MHz clock and hsync+vsync pulses.

The Raspi doesn't have a dedicated digital video input interface besides the camera connector which is IMHO hard to play with.
I would try writing a kernel module sampling some GPIOs in software. This is a time critical process so it must be done in a kernel module with interrupts disabled etc.. Ideally this kernel module is implemented as a v4l2 capture driver.

Alternatively, you might look for a FPGA HAT board, but I have no experience with this.

hth

KnarfB

pieroc91
Posts: 3
Joined: Fri Jun 29, 2018 2:08 pm

Re: Raspberry and a vintage video ADC

Mon Jul 16, 2018 2:28 pm

Hi KnarfB, thanks for your answer.

Yes, you got it exactly as it is.

Vsync and Hsync can might be recreated in postprocess i guess since all the pictures will have same width and height.

but still process has to be very precise since the first hsync signal must be sent from the PI as a register. Attached is a document with all the registers.

Main concern is that the PI is fast enough to record a 6mhz synced 8bit parallel data signal.

The FPGA is quite dificult, since i'm in argentina we don't have much of that, even raspberrys are very expensive, cheapest ones starts at 50dls.

Also, here are the schematics and original source code in PL/M : http://www.jemcgarvey.com/files/DCSschematics/

Thanks!
Last edited by pieroc91 on Mon Aug 27, 2018 1:25 pm, edited 2 times in total.

KnarfB
Posts: 194
Joined: Wed Dec 14, 2016 10:47 am
Location: Germany

Re: Raspberry and a vintage video ADC

Wed Jul 18, 2018 10:29 am

Hi pieroc91,

I made some tests with a kernel module, but a continous sampling rate of 6 MHz seems to be too fast to be achieved in software (even with direct MMIO register access in assembler).
This is consistent with other projects I have seen like https://github.com/richardghirst/Panalyzer having 1 MHz sample rate.
So, you IMHO will need some extra hardware.

I would really like to see your camera working. You might also use a microcontroller(board) which gives you better real-time control, maybe with an USB output which connects to a PC or Raspi or ...

KnarfB

pieroc91
Posts: 3
Joined: Fri Jun 29, 2018 2:08 pm

Re: Raspberry and a vintage video ADC

Wed Jul 18, 2018 3:04 pm

Thanks a lot Knarfb, thanks in the insight of Panalizer, which is an amazing project to use for other stuff.

and yes you are right, a Pi is not fast enough as it seems, tho is going to be useful on the second part of the project (if it evolves) for making an interface and storage the pictures to a regular SD card, In short, making it a non tethered machine.

well now i guess i'm starting to look what kind of hardware can do the job.

Thanks a lot!!

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