VGA and PAL output from FPGA

I'm after a bit of advice on selecting some parts for a 'hobbyist' 
project which may eventually turn into a commercial product...

I'm developing a board with an FPGA which will produce RGB digital 
output ultimately for display on RGB (15kHz), VGA and PAL/NTSC composite 
video. Not necessarily simultaneously - worst case is a different FPGA 
image for the former two options.

I've some experience with generating monochrome CVBS and VGA output from 
an FPGA, so I believe I have a handle on the technical aspects. But I'd 
like to offload much of the work (especially the PAL) to COTS parts, and 
this is where I don't have much experience.

First of all, is there a single encoder chip that is capable of 
outputing *both* RGB (15kHz and VGA) and PAL/NTSC (again, not 
necessarily at the same time)? For example, an RGB->PAL encoder with a 
'pass-thru' mode (which basically acts like a video DAC).

Failing that, I'm looking at the Chrontel CH7003 and Averlogic AL100/128 
PAL encoders to do half the job. I'm hoping that they are capable of 
running in slave mode (they accept the pixel clock) in some funky 
resolutions approximating but not equal to 'standard' VGA (horizontal) 
resolutions?

I'd complement that with a simple triple video DAC (like the ADV7125 
used on the Xilinx dev boards) for RGB (15kHz) and VGA outputs.

In either case/mode, I'd be doing the video timing (except for PAL 
output) in the FPGA and so supplying the pixel clock and syncs etc to 
the devices (they're slaves). Different FPGA images might run at 
different resolutions, some may target 15kHz monitors whilst others may 
target VGA, etc, hence the 'flexible' requirements.

As far as my approach to the problem is concerned, am I on the right 
track here? Did I choose the best/cheapest/easiest-to-get parts? Or is 
there a better/simpler/cheaper way to do it?

Keep in mind that it is only a spare-time project atm and although I'm 
willing to make some investment, obviously I'll only be ordering and 
manufacturing in very small quantities at this point. At best you could 
consider it a 'niche' product so even if I did eventually realise a 
commercial product, it would still be low volume.

TIA for any help/hints/suggestions!

Regards,
Mark

"Mark McDougall" <markm@vl.com.au> schrieb im Newsbeitrag
news:434d17b6$0$16843$5a62ac22@per-qv1-newsreader-01.iinet.net.au...
> I'm after a bit of advice on selecting some parts for a 'hobbyist'
> project which may eventually turn into a commercial product...
>
> I'm developing a board with an FPGA which will produce RGB digital
> output ultimately for display on RGB (15kHz), VGA and PAL/NTSC composite
> video. Not necessarily simultaneously - worst case is a different FPGA
> image for the former two options.
>
> I've some experience with generating monochrome CVBS and VGA output from
> an FPGA, so I believe I have a handle on the technical aspects. But I'd
> like to offload much of the work (especially the PAL) to COTS parts, and
> this is where I don't have much experience.
>
> First of all, is there a single encoder chip that is capable of
> outputing *both* RGB (15kHz and VGA) and PAL/NTSC (again, not
> necessarily at the same time)? For example, an RGB->PAL encoder with a
> 'pass-thru' mode (which basically acts like a video DAC).
>
> Failing that, I'm looking at the Chrontel CH7003 and Averlogic AL100/128
> PAL encoders to do half the job. I'm hoping that they are capable of
> running in slave mode (they accept the pixel clock) in some funky
> resolutions approximating but not equal to 'standard' VGA (horizontal)
> resolutions?

CH7003 can do PAL, NTSC and VGA check out the datasheet
its not clear if the VGA mode with CH7003 can accept any format but a lot of
formats are supported so if you are happy with them then CH7003 can do it
all.

or check ADI (www.analog.com) video encoders, they most do either pal/secam
or pure RGB dac

sure make sure you select a component that you actually can purchase, ADI
can send free samples, with Chrontel check availability in sample qty
Antti

On Thu, 13 Oct 2005 00:05:33 +1000, Mark McDougall <markm@vl.com.au> wrote:

>I'm after a bit of advice on selecting some parts for a 'hobbyist' 
>project which may eventually turn into a commercial product...
>
>I'm developing a board with an FPGA which will produce RGB digital 
>output ultimately for display on RGB (15kHz), VGA and PAL/NTSC composite 
>video. Not necessarily simultaneously - worst case is a different FPGA 
>image for the former two options.
>
>I've some experience with generating monochrome CVBS and VGA output from 
>an FPGA, so I believe I have a handle on the technical aspects. But I'd 
>like to offload much of the work (especially the PAL) to COTS parts, and 
>this is where I don't have much experience.
>
>First of all, is there a single encoder chip that is capable of 
>outputing *both* RGB (15kHz and VGA) and PAL/NTSC (again, not 
>necessarily at the same time)? For example, an RGB->PAL encoder with a 
>'pass-thru' mode (which basically acts like a video DAC).
>
>Failing that, I'm looking at the Chrontel CH7003 and Averlogic AL100/128 
>PAL encoders to do half the job. I'm hoping that they are capable of 
>running in slave mode (they accept the pixel clock) in some funky 
>resolutions approximating but not equal to 'standard' VGA (horizontal) 
>resolutions?
>
>I'd complement that with a simple triple video DAC (like the ADV7125 
>used on the Xilinx dev boards) for RGB (15kHz) and VGA outputs.
>
>In either case/mode, I'd be doing the video timing (except for PAL 
>output) in the FPGA and so supplying the pixel clock and syncs etc to 
>the devices (they're slaves). Different FPGA images might run at 
>different resolutions, some may target 15kHz monitors whilst others may 
>target VGA, etc, hence the 'flexible' requirements.
>
>As far as my approach to the problem is concerned, am I on the right 
>track here? Did I choose the best/cheapest/easiest-to-get parts? Or is 
>there a better/simpler/cheaper way to do it?
>
>Keep in mind that it is only a spare-time project atm and although I'm 
>willing to make some investment, obviously I'll only be ordering and 
>manufacturing in very small quantities at this point. At best you could 
>consider it a 'niche' product so even if I did eventually realise a 
>commercial product, it would still be low volume.
>
>TIA for any help/hints/suggestions!
>
>Regards,
>Mark

Philips do some video encoders that may be worth a look - e.g. SAA7126 I think there are a few
varients in the range - often used in set-top boxes so should be fairly cheap, and you may be able
to scavenge some samples from dead boxes.
For VGA, if you only need TV resolution you may be able to do some tricks, e.g. generating vga sync
while feeding suitably tweaked fake ccir sync to the encoder.

On Wed, 12 Oct 2005 16:05:33 +0200, Mark McDougall <markm@vl.com.au> wrote:

> I'm developing a board with an FPGA which will produce RGB digital  
> output ultimately for display on RGB (15kHz), VGA and PAL/NTSC composite  
> video. Not necessarily simultaneously - worst case is a different FPGA  
> image for the former two options.

http://elm-chan.org/works/crtc/report.html


-- 
the penguins are psychotic
aka just smile and wave

On Thursday, in article <op.syldd6szp7sh2t@lozko.mshome.net>
     citizenr@gmail.com "koko" wrote:
>On Wed, 12 Oct 2005 16:05:33 +0200, Mark McDougall <markm@vl.com.au> wrote:
>> I'm developing a board with an FPGA which will produce RGB digital
>> output ultimately for display on RGB (15kHz), VGA and PAL/NTSC composite  
>> video. Not necessarily simultaneously - worst case is a different FPGA  
>> image for the former two options.
>
>http://elm-chan.org/works/crtc/report.html

Hmmm, note its o/p is RGB interlaced, and uses a Sony CXA chip which I
would check availability on first as many of those are no longer in
production and have not been for a few years.

-- 
Paul Carpenter          | paul@pcserviceselectronics.co.uk
<http://www.pcserviceselectronics.co.uk/>    PC Services
<http://www.gnuh8.org.uk/>              GNU H8 & mailing list info
<http://www.badweb.org.uk/>             For those web sites you hate

On Thu, 13 Oct 2005 20:20:56 +0200, Paul Carpenter  
<paul$@pcserviceselectronics.co.uk> wrote:

>> http://elm-chan.org/works/crtc/report.html
>
> Hmmm, note its o/p is RGB interlaced, and uses a Sony CXA chip which I
> would check availability on first as many of those are no longer in
> production and have not been for a few years.

hmm Motorola MC1377P for example, its only PAL color encoder, any will do

-- 
the penguins are psychotic
aka just smile and wave

koko wrote:

> http://elm-chan.org/works/crtc/report.html

Thanks, but it uses the CXA1645, which converts analogue RGB.

I have raw *digital* RGB output from an FPGA, which I want to convert to 
analogue RGB (15kHz), VGA, and composite (not necessarily at the same time).

I'm favouring a triple video DAC for RGB & VGA atm (ADVXXX), and encoder 
for composite/s-video (like the CH7003), both driven off the FPGA 
output. Timing is generated in the FPGA (mainly to enable time-sliced 
access to some SRAM, so the pixel clock will be some synchronous 
dividend of the main FPGA system clock), and the encoder will be a slave.

Regards,
Mark

Mike Harrison wrote:

> Philips do some video encoders that may be worth a look - e.g.
> SAA7126 I think there are a few varients in the range - often used in
> set-top boxes so should be fairly cheap, and you may be able to
> scavenge some samples from dead boxes. 

They all seem to be YUV inputs. I haven't considered what that would 
require in the FPGA. I understand it's not too difficult to transform 
(digital) RGB to YUV? Any comments?

Regards,
Mark

On Fri, 14 Oct 2005 03:22:40 +0200, Mark McDougall <markm@vl.com.au> wrote:

> I have raw *digital* RGB output from an FPGA, which I want to convert to  
> analogue RGB (15kHz), VGA, and composite (not necessarily at the same  
> time).

sory, I hit reply after reading 2 first lines, my bad :(

> I'm favouring a triple video DAC for RGB & VGA atm (ADVXXX), and encoder  
> for composite/s-video (like the CH7003), both driven off the FPGA  
> output. Timing is generated in the FPGA (mainly to enable time-sliced  
> access to some SRAM, so the pixel clock will be some synchronous  
> dividend of the main FPGA system clock), and the encoder will be a slave.

all that comes to my mind is MC1377P, LM1889, TEA2000 (can you say  
dinosaur? 85 was a good year). I did few circuits with the first one and  
they worked reasonably well. But forget about simultaneous PAL/VGA with  
those.


-- 
I really have no idea what this means. And since I can't install linux on  
it, I'm gonna go back to surfing pr0n.
the penguins are psychotic / just smile and wave

On Tue, 18 Oct 2005 04:37:32 +0200, hackbox.info <hackbox.info@gmail.com>  
wrote:

> all that comes to my mind is MC1377P, LM1889, TEA2000 (can you say  
> dinosaur? 85 was a good year). I did few circuits with the first one and  
> they worked reasonably well. But forget about simultaneous PAL/VGA with  
> those.

or just output analog VGA from your pcb and cut development/soldering time  
buying this box
http://www.chipzone.com/shop/showdetl.cfm?DID=12&Product_ID=229
pinout http://ucon64.sourceforge.net/ucon64misc/conn.html#11
Looks unprofessional, butt ugly, bulky, but only $20 new (free/beer from a  
friend/ebay), tested and works great.
Inside you will find MC13077P, one transistor and RF modulator.

-- 
I really have no idea what this means. And since I can't install linux on  
it, I'm gonna go back to surfing pr0n.
the penguins are psychotic / just smile and wave