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Television Standards Converters, Modulators etc Standards converters, modulators anything else for providing signals to vintage televisions.

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Old 20th Aug 2011, 1:56 pm   #141
Andy Green
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Default Re: Simple memory card player idea

Fair play to you Karen - nice job!
(I also need to buckle down and learn PIC programming)
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Old 20th Aug 2011, 2:46 pm   #142
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Quote:
(I also need to buckle down and learn PIC programming)
Microchip do a super range of tools including a C compiler for nothing, Farnell sell the http://uk.farnell.com/microchip/dm24...ent/dp/1605296 and is a very good start. 40 quid, a laptop and you are away!
 
Old 20th Aug 2011, 6:37 pm   #143
julie_m
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Default Re: Simple memory card player idea

Anyone know if the PIC development stuff is either available in Source Code, or usable with WINE? Kat?
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Old 21st Aug 2011, 1:19 am   #144
Karen O
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Fair play to you Karen - nice job!
Thank you Andy
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Old 21st Aug 2011, 4:49 pm   #145
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Default Re: Simple memory card player idea

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Originally Posted by ajs_derby View Post
Anyone know if the PIC development stuff is either available in Source Code, or usable with WINE? Kat?
It's been a few years but I used to run the Microchip MPLab stuff under wine I seem to remember it was a pain getting all the directories right but then it is anyway with MPLab!

There are some Linux-native PIC development tools too...gputils springs to mind

I even made my own PIC programmer that ran on the serial port in Linux...if you're interested I've probably still got the sourcecode somewhere...trouble was making changes for each different PIC chip

Karen, any chance of putting your sourcecode for the PIC up somewhere (or sending it by PM)? I'd be interested in a look see, though I'd still like to do a "format neutral" version that just streams samples out. I've got some weird experimentation to do to try and work out what is going on with a Prototype ART decoder that I need to figure out and being able to feed it a picture would be great!

Dom

PS: Congrats on getting a nice glitch free picture so quickly!
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Old 21st Aug 2011, 9:35 pm   #146
Andy Green
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Default Re: Simple memory card player idea

I think the Pinguino PIC development system is available for Linux and Mac as well as Windows
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Old 21st Aug 2011, 9:44 pm   #147
Karen O
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Hi Dominic,

I'm documenting the project at the moment. I'll let you know when its ready for release.

I too am giving thought to a more continuous replay but for high end NBTV (e.g. 60 lines), using an SD card, aiming at a video bandwidth of around 100kHz.

Something to bear in mind if you go for continuous replay - my 405 line player exploits the frame blanking period to place time between issuing the read command, which happens during frame sync, and the data transfers that happen during the active picture lines. This gives the card around 1msec to sort itself out.

If you want continuous transfer at rates comparable to my 405 line data transfer rate (6.25MHz) without a break then you are going to have to use a lot of buffering and this will force you to use a more conventional approach with a much more powerful processor and memory. It might be easier to design a video latch peripheral for a small Linux computer.

Thanks for the congrats. I'll have to look out for a meet or convention and bring it along to show everybody!
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Old 28th Aug 2011, 10:52 am   #148
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Default Re: Simple memory card player idea

Just Watched the Video, I have to say well done Karen, that's brilliant.

I do some PIC coding but only simple stuff like a Geiger counter interface and a couple of motorcycle engine management based projects, nothing on this level of complexity.

What's next? a file system, user interface and a hard disk?

Dave.
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Old 29th Aug 2011, 9:18 am   #149
Kat Manton
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Default Re: Simple memory card player idea

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Originally Posted by Karen O View Post
No, no, no - much better to use under-powered hardware, personal whim and what happens to be in my junkbox.
I wholeheartedly concur. The trouble is my junkbox hosts Z80 and associated peripheral chips, clearly I need some 21st century under-powered hardware...

Quote:
Originally Posted by Karen O View Post
But don't get the idea that it's easy - I have coded many time-critical PIC applications where it is trying to do two or three things at once and so quickly that interrupts are useless (I rarely use interrupts!) The CF player is no exception. You go mad counting cycles
Been there, done that got... well, I got a couple of sweatshirts from the company I worked for. Several products I wrote code for (Z80/HD64180) involved interleaving bits of non-time-critical code with time-critical code, using the former to create the delays for the latter... and a lot of counting cycles (and dire warnings in the comments against modifying bits without counting cycles again.)

I did notice this in Wikipedia - PIC microcontroller - Performance:
Quote:
The constant interrupt latency allows PICs to achieve interrupt driven low jitter timing sequences. An example of this is a video sync pulse generator.
Cool, Wikipedia says I can use it as an SPG, so it must be true...

Quote:
Originally Posted by ajs_derby View Post
Anyone know if the PIC development stuff is either available in Source Code, or usable with WINE? Kat?
I'm going to give 'MPLABĀ®' a whirl; from what I've read on various forums and WineHQ, it sounds like it's mostly working. (First I need to turn my programmer into a programmer...)

Drifting finally back to the topic, now I've caught up; excellent work, Karen. I'll be interested in a look at this once you've finished documenting it and released it

Kat
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Old 27th Sep 2011, 1:42 am   #150
Karen O
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Default Re: Simple memory card player idea

I've finished building my ETF modulator and used it successfully with my CF player. I would recommend the ETF modulator - an excellent design.
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Old 27th Sep 2011, 11:56 am   #151
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Default Re: Simple memory card player idea

Not that I understand much of the above , but does an Aurora take a to-air(Sky/Cable/Freeview/Analogue TV signal on input and convert immediately to 405line output for viewing? Can your system output to 405line video recorders ( tape machines from philips and the like ).

Ian
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Old 27th Sep 2011, 12:05 pm   #152
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Default Re: Simple memory card player idea

An Aurora SCRF405A takes any 625 line video signal and gives 405 line video and modulated RF outputs. The video can come from any Freeview box, Sky box, DVD player etc. Conversion is immediate and real time. Well perhaps a few 100 microseconds delay

http://www.tech-retro.com/Aurora_Design/Home.html

Other versions give 819 lines, 441 lines, 30 lines etc

If Karen's design outputs a standard 405 line video signal this can be recorded on many VCRs. Tends to work better on older machines that don't have too much fancy processing. It will not work with DVD recorders. But since the Aurora is readily available there is no real reason to do this nowadays.
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Old 7th Oct 2011, 11:53 pm   #153
Karen O
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Default Re: Simple memory card player idea

I've just watched part 1 of 'The Dalek Invasion of Earth' on my CF player and using my ETF modulator!

Considering the recording has been through 405-to-625 and back again it's pretty good.

I had one problem: The C program I wrote had to be recompiled for 64 bit file offsets as it couldn't read the 6GB raw video file!
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