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Need Help with Video overlay

B

Bubba

Jan 1, 1970
0
I need help with designing a circuit. I am a software and mechanical
engineer and I am hopeing someone out there can help. I need a circuit that
when it recieves power it overlays a timer on the screen of a tv and counts
down. Then when it hits 0 it turns off the video signal. I know the main
chip for the overlay that I want to use will be the STV5730 but I am not
sure if this will hold all the programming logic, or do I have to have a 555
chip do the coutdown and then tell the STV5730 to turn off the signal. It
needs to be a stand alone circuit and not hooked up to the computer. Can
someone please help I have been looking on the internet for information for
days. Thanks in Advance, Joey
 
S

Spehro Pefhany

Jan 1, 1970
0
I need help with designing a circuit. I am a software and mechanical
engineer and I am hopeing someone out there can help. I need a circuit that
when it recieves power it overlays a timer on the screen of a tv and counts
down. Then when it hits 0 it turns off the video signal. I know the main
chip for the overlay that I want to use will be the STV5730 but I am not
sure if this will hold all the programming logic, or do I have to have a 555
chip do the coutdown and then tell the STV5730 to turn off the signal. It
needs to be a stand alone circuit and not hooked up to the computer. Can
someone please help I have been looking on the internet for information for
days. Thanks in Advance, Joey

You are going to need some kind of computer or microcontroller to tell
the OSD chip what to display. Firmware will have to be written for it.
It's also not a good choice for a new product, as it's an obsolete
chip.

Other than that, it's not a big project. The micro communicates with
the STV5730 over an SPI type serial bus with only a few lines. The
micro can easily keep track of the time as well.

Best regards,
Spehro Pefhany
 
J

John Jardine

Jan 1, 1970
0
Bubba said:
I need help with designing a circuit. I am a software and mechanical
engineer and I am hopeing someone out there can help. I need a circuit that
when it recieves power it overlays a timer on the screen of a tv and counts
down. Then when it hits 0 it turns off the video signal. I know the main
chip for the overlay that I want to use will be the STV5730 but I am not
sure if this will hold all the programming logic, or do I have to have a 555
chip do the coutdown and then tell the STV5730 to turn off the signal. It
needs to be a stand alone circuit and not hooked up to the computer. Can
someone please help I have been looking on the internet for information for
days. Thanks in Advance, Joey
They (Philips?) stopped making that superb STV OSD chip a couple of years
ago. The other OSD makers also seem to have followed suit as well.
NEC, Mitsubishi, Panasonic. Fujistsu (Renasas) have between them a half
dozen 'bare bones' OSD chips in their catalogues but are talking MOQs of
10,000 and no support otherwise. They also throw a 'deaf un' if pressed on
pricing or possible obsolescence.
Maxim have an 8 channel device but it's rather expensive (and no colour!).
I've been told that the makers have been pulling out of OSD as the market
for satelite receiving equipment has saturated.
There's still a general demand for these things yet there's none to be had.
It's a near impossible task to try to viably duplicate the OSD functions
using discrete micros, fast character stores, video switches, chroma
modulators etc.

(There's a big hole that needs filling. I occasionally wonder at the level
of costs involved in having an (or 'the') STV5730 type OSD chip
manufactured :)

http://www.rickard.gunee.com/projects/video/pic/howto.php has a nice PIC
page on video overlays. there's also a couple of PIC video timer displays
(somewhere) out there as well.

regards
john
 
S

Spehro Pefhany

Jan 1, 1970
0
(There's a big hole that needs filling. I occasionally wonder at the level
of costs involved in having an (or 'the') STV5730 type OSD chip
manufactured :)

There's still a bunch floating around (thousands and thousands), but
the price tends to increase over time as the supply decreases. There
are 2/3 as many left at one distributor as were there only 3 months
ago, and some distributors have 0. If only a fixed number are
required, it might be feasible to just buy them up at the start of the
project.

Best regards,
Spehro Pefhany
 
W

Winfield Hill

Jan 1, 1970
0
Spehro Pefhany wrote...
There's still a bunch floating around (thousands and thousands),
but the price tends to increase over time as the supply decreases.

[ snip ]

Partminer shows quantities in stock at various surplus houses,
without revealing who they are: 3012, 954, 13162, 24820, 3920.
And Future has a tube.

Thanks,
- Win

whill_at_picovolt-dot-com
 
S

Steve Roberts

Jan 1, 1970
0
Do a google for On Screen Display and PIC or

Do a Google for "BOB II" 70$ a unit but probably licensable.

Steve Roberts
 
J

Jan Panteltje

Jan 1, 1970
0
They (Philips?) stopped making that superb STV OSD chip a couple of years
ago. The other OSD makers also seem to have followed suit as well.
NEC, Mitsubishi, Panasonic. Fujistsu (Renasas) have between them a half
dozen 'bare bones' OSD chips in their catalogues but are talking MOQs of
10,000 and no support otherwise. They also throw a 'deaf un' if pressed on
pricing or possible obsolescence.
Maxim have an 8 channel device but it's rather expensive (and no colour!).
I've been told that the makers have been pulling out of OSD as the market
for satelite receiving equipment has saturated.
There's still a general demand for these things yet there's none to be had.
It's a near impossible task to try to viably duplicate the OSD functions
using discrete micros, fast character stores, video switches, chroma
modulators etc.

(There's a big hole that needs filling. I occasionally wonder at the level
of costs involved in having an (or 'the') STV5730 type OSD chip
manufactured :)

http://www.rickard.gunee.com/projects/video/pic/howto.php has a nice PIC
page on video overlays. there's also a couple of PIC video timer displays
(somewhere) out there as well.

regards
john
The Google for:
SAA5246A_CNV_3-15.ps
SAA5246A_CNV_3.pdf
teletext chips (Philips) make for a great OSD system.
I have used these in several projects.
You need some static RAM chip to (few kB).
The chips have composite and RGB out.
I2c drive, and my drivers and most libs are available
open source in C.
Siemens also had one with build in RAM. IIRC.
 
J

John Jardine

Jan 1, 1970
0
Winfield Hill said:
Spehro Pefhany wrote...
There's still a bunch floating around (thousands and thousands),
but the price tends to increase over time as the supply decreases.

[ snip ]

Partminer shows quantities in stock at various surplus houses,
without revealing who they are: 3012, 954, 13162, 24820, 3920.
And Future has a tube.

Thanks,
- Win

whill_at_picovolt-dot-com
Thanks for looking :)
Trouble is, I need about 6000 a year for a product with at least a 10 years
foreseeable life. A similar Philips OSD part used in the existing equipment
was also summarily obsoleted 2 years ago. Surplus outlets are now wanting
£15 each. (£5 originally). The STV stock holdings are really *tempting* but
I was hoping for a long term working relationship with this customer.
Grabbing the money and headin' for the hills is a bit final :). Albeit,
they have suggested that a quick one off purchase of say 10-15000 of surplus
chips may be a final option.

As also with many designers, with the beancounters withdrawing chips right
left and centre I've recently become *very* nervous of designing-in any neat
but single-sourced IC's.
It's an ill wind etc ... Just doin a design for a small PCB plugin as
replacement for a recently obsoleted IC. It's surprising what can be done
with a few opamps and comparitors!.
regards
john
 
J

John Jardine

Jan 1, 1970
0
Jan Panteltje said:
The Google for:
SAA5246A_CNV_3-15.ps
SAA5246A_CNV_3.pdf
teletext chips (Philips) make for a great OSD system.
I have used these in several projects.
You need some static RAM chip to (few kB).
The chips have composite and RGB out.
I2c drive, and my drivers and most libs are available
open source in C.
Siemens also had one with build in RAM. IIRC.

Indeed. These chips are very suitable for OSD. When I looked (last month) I
was picking up bad vibes as to their future availability. Philips have been
ruthlessly winnowing much of their consumer chip ranges (including a couple
of Teletext items) and with their dropping the extremely useful STV range I
felt it didn't bode well for the even more specialist TeleText chips.
I get the feeling that all the chip makers seemed to get their heads
together and act in unison to drop their non-profitable items. Maybe we can
now look forward to a few years of stability.

regards
john
 
J

Jan Panteltje

Jan 1, 1970
0
As also with many designers, with the beancounters withdrawing chips right
left and centre I've recently become *very* nervous of designing-in any neat
but single-sourced IC's.
It's an ill wind etc ... Just doin a design for a small PCB plugin as
replacement for a recently obsoleted IC. It's surprising what can be done
with a few opamps and comparitors!.
regards
john
A solution may be a FPGA.
Such an OSD device is only some counters, a horizontal PLL, and a ROM for
the character generator.
The PLL to lock to incoming video.
I have recently done some of that stuff with Xilinx FPGA for a line doubler.
Loading the FPGA internal RAM (say you have 2 kB available in a specific one)
from the FLASH ROM at startup or (some micro) with characters should be
enough?
In the old past I had 2 kB EPROM char chenerator (2716)?
So a Spartan 2 or 2e 200 should be enough, and perhaps can replace much more
logic and other stuff on your board.
Even if the FPGA is no longer available, but bigger ones make inroads, you
can port your HDL code.
This way seems to be a better and safer way perhaps for the future.
Although FPGA / HDL programming has a steep learning curve, I am happy I
went that way and now am free to make what I want.
Perhaps in the future it will be more and more code for hardware, and less
and lees custom chips?
Some years ago I was making fun at people who added two voltages not with
2 resistors, but with 2 AD then a micro or DSP and a DA ;-)
But now with FPGA it is very tempting to go digital immediatly and do all
filtering and processing in that chip.
It also makes a step in speed, way way faster then micro processors can.
Then also several processor cores are already available in HDL, so you
may save on components, micros, DSP, glue logic, what not.
Interested to hear your experiences in that field.
Maybe for a new Art Of Electronics this would be a good chapter to have.
JP
 
J

Jan Panteltje

Jan 1, 1970
0
Indeed. These chips are very suitable for OSD. When I looked (last month) I
was picking up bad vibes as to their future availability. Philips have been
ruthlessly winnowing much of their consumer chip ranges (including a couple
of Teletext items) and with their dropping the extremely useful STV range I
felt it didn't bode well for the even more specialist TeleText chips.
I get the feeling that all the chip makers seemed to get their heads
together and act in unison to drop their non-profitable items. Maybe we can
now look forward to a few years of stability.

regards
john
This could have to do with the coming of digital TV here.
Analog will go in a couple of years, and with it analog teletext chips.
Perhaps better stock up on a few for repairs :)
 
P

Pat Ford

Jan 1, 1970
0
Jan Panteltje said:
On a sunny day (Tue, 2 Mar 2004 02:14:30 -0000) it happened "John Jardine"
snip

This way seems to be a better and safer way perhaps for the future.
Although FPGA / HDL programming has a steep learning curve, I am happy I
went that way and now am free to make what I want.
Perhaps in the future it will be more and more code for hardware, and less
and lees custom chips?

Do you have any recommendations for books or websites on hdl programming?

snip
Maybe for a new Art Of Electronics this would be a good chapter to have.
JP

I wish Win would hurry up with the new AOE, I want one but I don't want to
get it twice.

Pat
 
J

Jan Panteltje

Jan 1, 1970
0
Do you have any recommendations for books or websites on hdl programming?
You should perhaps ask in comp.arch.fpga
get a evaluation board for some FPGA, and get the (often) free soft, and
start trying some things.
There is a FPGA FAQ at http://www.fpga-faq.com
The FPGA manufacturers have a HUGE technical application database, where you
can find examples of almost anything, if you want to know how it is done.
Look for example at the Xilinx site, search for application notes.
There is also Altera, Actel, etc..
There are 2 main HDL languages in use, Verilog and VHDL.
Each has its supporters etc...
There are several documents for free on the net, I have collected many many
MB of stuff over the last year or so.
www.opencores.com has some interesting open source projects and processor
cores for FPGA.
It is a learning process, I am still learning, that never ends, these thing
get bigger and faster, faster then you can keep up perhaps.
Also it requires significant re-thinking if you come from a software
background ....
For me I come from a hardware background, and it is very familiar, but still
digital filters etc.. take a lot of time to get to really understand.
Hang out in that newsgroup perhaps, it may give you hints.
JP
 
J

John Jardine

Jan 1, 1970
0
Jan Panteltje said:
A solution may be a FPGA.
Such an OSD device is only some counters, a horizontal PLL, and a ROM for
the character generator.
The PLL to lock to incoming video.
I have recently done some of that stuff with Xilinx FPGA for a line doubler.
Loading the FPGA internal RAM (say you have 2 kB available in a specific one)
from the FLASH ROM at startup or (some micro) with characters should be
enough?
In the old past I had 2 kB EPROM char chenerator (2716)?
So a Spartan 2 or 2e 200 should be enough, and perhaps can replace much more
logic and other stuff on your board.
Even if the FPGA is no longer available, but bigger ones make inroads, you
can port your HDL code.
This way seems to be a better and safer way perhaps for the future.
Although FPGA / HDL programming has a steep learning curve, I am happy I
went that way and now am free to make what I want.
Perhaps in the future it will be more and more code for hardware, and less
and lees custom chips?
Some years ago I was making fun at people who added two voltages not with
2 resistors, but with 2 AD then a micro or DSP and a DA ;-)
But now with FPGA it is very tempting to go digital immediatly and do all
filtering and processing in that chip.
It also makes a step in speed, way way faster then micro processors can.
Then also several processor cores are already available in HDL, so you
may save on components, micros, DSP, glue logic, what not.
Interested to hear your experiences in that field.
Maybe for a new Art Of Electronics this would be a good chapter to have.
JP
Jan.
I have precisely -NO- experience with the gate array chips and was
therefore interested in your reply to Pat. I keep spotting these things in
the catalogues and invariably stop and drool over the <20nS speeds they
offer. When I see a price though, I cough, have to pretend I haven't seen
the chip and quickly turn the page :).
With much of the stuff I do, I can offer a customer various options on
price-v-performance. 9 times out of 10 they plump for a low product
manufacturing cost and I can end up squeezing blood out of a cheap PIC
chip. I *loathe* those damned PIC chips, their weird internals, their cruddy
software, their useless documention but they have the annoying feature of
being relatively cheap and available everywhere.
For the OSD thing I'd started to look at a cheap 'bare-bones' option of
using a PIC controlling a fast (dot) shift register, 4k-8k RAM character dot
store, video dot/signal switch and sync' clock logic etc. Essentially the
PIC "only" has to provide character line sequencing, RS485 comms and
counting video lines and frames. The high speed stuff being handled by HC
logic. A 20MHz PIC version might just been viable. Final cost maybe the
equiv' of $8.
I actually wanted something like 20x20 character cells (PAL) hence the
resulting serial dot rates would be perfect for a FPGA chip but the apparent
cost could be higher.
Having said that, the speed of the FPGA's open up many other tasty
possibilities where the PICs can't even begin to tread and normal analogue
methods rule hence I'm looking to follow up your leads.
ps : On past occasions when I've looked in on Xilinx etc I've had
difficulty getting any sense out of what they are actually offering as
products (or even tasters of what they could do). I got the distinct
impression that they were marketing outfits run by programmers, who between
them hadn't a clue about real world aspects of the products they made.
Hopefully this is history :)
regards
john
 
J

Jan Panteltje

Jan 1, 1970
0
Jan.
I have precisely -NO- experience with the gate array chips and was
therefore interested in your reply to Pat. I keep spotting these things in
the catalogues and invariably stop and drool over the <20nS speeds they
offer. When I see a price though, I cough, have to pretend I haven't seen
the chip and quickly turn the page :).
With much of the stuff I do, I can offer a customer various options on
price-v-performance. 9 times out of 10 they plump for a low product
manufacturing cost and I can end up squeezing blood out of a cheap PIC
chip. I *loathe* those damned PIC chips, their weird internals, their cruddy
software, their useless documention but they have the annoying feature of
being relatively cheap and available everywhere.
For the OSD thing I'd started to look at a cheap 'bare-bones' option of
using a PIC controlling a fast (dot) shift register, 4k-8k RAM character dot
store, video dot/signal switch and sync' clock logic etc. Essentially the
PIC "only" has to provide character line sequencing, RS485 comms and
counting video lines and frames. The high speed stuff being handled by HC
logic. A 20MHz PIC version might just been viable. Final cost maybe the
equiv' of $8.
I actually wanted something like 20x20 character cells (PAL) hence the
resulting serial dot rates would be perfect for a FPGA chip but the apparent
cost could be higher.
Having said that, the speed of the FPGA's open up many other tasty
possibilities where the PICs can't even begin to tread and normal analogue
methods rule hence I'm looking to follow up your leads.
ps : On past occasions when I've looked in on Xilinx etc I've had
difficulty getting any sense out of what they are actually offering as
products (or even tasters of what they could do). I got the distinct
impression that they were marketing outfits run by programmers, who between
them hadn't a clue about real world aspects of the products they made.
Hopefully this is history :)
regards
john
Hi, well I have also very little confidence in Xilinx programmers, their free
webpack software is bloated (needed they say), and the error messages
send you on a long search in the wrong direction.
Given that, it IS possible to write HDL code with it.
I got myself a board with a Spartan 2 (Xilinx 200k gates, 5 V compatible) for
about 100$ from www.digilent.com I think it was.
That, and the free xilinx soft got me started.
It is true these things are very expensive (compared to PIC), but if you have
a lot of logic, then it makes sense.
Use whatever is optimal for your application.
In a way it ads to what you can make, simple as that.
That I know about FPGA does not make me not use PICs!
As for the PICs well, small stack space and register banks, but I am used to that now.
It is not bad at all.
The thing you describe reminds me of Sinclair zx80, he also used a shift register
for the character rows, and used the z80 refresh register in a clever way too, all that at
3. something MHz.
With a 20 MHz PIC and an 8 bits shift you should be able to do it?
As for what you can do with the FPGA have a look at the application notes on the xilinx site.
Xilinx has a ftp server with many aplication notes.
Or you could type 'xapp' in google.
Anyways all these things take a lot of time to get to grips with :)
JP
 
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