Tv Display with Picaxe?

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ChedderCheeser

Senior Member
Hi all, I was wondering, is is possible to display.. stuff on a tv using the yellow, 2 wire, coax. cable? I am using a picaxe 08M and will run it at 8MHz if needed. I want to have and use a O8M2, but I dont have one. I know its faster, and thats why. But yea, ... I always wondered how you can get VIDEO from 2 wires... Can someone explain this to me PLEASE? :D Also, if there is some example code.. that would be nice. I'm sorry if I'm asking much of you all... I just was wonderin. :D THANKS!!!
 
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ChedderCheeser

Senior Member
So.. i cannot just.. hook the cable to a picaxe and call it that? Even if it was at 32MHz. Well.. i guess i'll go to a big LCD. What about VGA? HDMI, or DVI?
 
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westaust55

Moderator
ChedderCheeser said:
So.. i cannot just.. hook the cable to a picaxe and call it that? Even if it was at 32MHz. Well.. i guess i'll go to a big LCD. What about VGA? HDMI, or DVI?
Click to expand...
@Chedder,
A "native" Microchip PIC chip running assembler/machine code executes functions quickly and even then the PIC is a little limited in what can be achieve with the more basic PIC chips.

A PICAXE chip from Rev Ed takes a PIC chip and has a bootloader and BASIC interpreter installed by Rev Ed so that you can program easily in the BASIC programming language. Using an interpreter greatly slows down the operating speed since each of your BASIC commands needs to be fetched, interprested into assembler and executed.
This is not just a speed issue for the PICAXE but for any microcontroller or microprocessing using interpreted BASIC.
The advantage of the PICAXE system is the cost and (once used to the programming and limitations) the ease of programming.


In considering the level of you many questions, with no disrespect but, IMHO you need to spend some time learning about the PICAXE system before considering significant projects.
 
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NXTreme

Senior Member
In some cases where the Picaxe just won't cut it (like this one) you could try using a different microcontroller as a go-between. The Parallax Propeller seems to be a fairly simple solution for video and audio. I've never used it, so I can't say much as to how you program it, but it might be worth a try.

I don't mean to "convert" others to different microcontrollers, quite the opposite in fact. However, as it's been said many, many times on these forums, horses for courses ;).
 
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ChedderCheeser

Senior Member
NXTreme said:
In some cases where the Picaxe just won't cut it (like this one) you could try using a different microcontroller as a go-between. The Parallax Propeller seems to be a fairly simple solution for video and audio. I've never used it, so I can't say much as to how you program it, but it might be worth a try.

I don't mean to "convert" others to different microcontrollers, quite the opposite in fact. However, as it's been said many, many times on these forums, horses for courses ;).
Click to expand...
ya mean like... use another micro as an adapter for the audio/video to the picaxe?
 
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NXTreme

Senior Member
Yes, srnet is correct there, the Propeller would act as a video and audio "adapter" for the Picaxe.

NXTreme said:
I've never used it, so I can't say much as to how you program it, but it might be worth a try.
Click to expand...
With a bit more searching, it appears you need a serial port (FTDI, actual serial port, whatever) with 3.3V signal levels to program the Prop. So, it might even be possible to re-purpose a Picaxe programming cable. However, I'm probably going off topic here...
 
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Grogster

Senior Member
For basic TV out, without too much to learn, use the TellyMate as manuka suggests.

In the image he posted(coded by me - manuka - you image thief!!! ;) :D ), this just gives a basic run-down of a system which is using that approach. You have your main PICAXE at the heart of the system, and you tell the TV-out adaptor what you want on the screen with serial commands, and the seperate TV-out chip does all the video processing.

This is pretty much exactly what most home computers did 20 years ago(Atari, Commodore 64, ZX Spectrum etc). They had a main CPU, and it would instruct the TV-out processor what it wanted and when - it was NOT directly done with the main CPU.

In the case of the TellyMate, it is B/W only - no colour, but most LCD's are not colour either. TM is great, can be set to all sorts of baud-rates, can be NTSC or PAL output, and most importantly IS EXTREMELY CHEAP. I think it is about NZ$15 for a kit from Batsocks with programmed MEGA8 CPU and PCB etc.
 
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westaust55

Moderator
This topic has been covered onthis forum before.
If you do a search here or Google the web you should find sources of commercially available modules to generate video from PICAXE data for TV or VGA.
Manuka has I believe mentioned one such module above.
 
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srnet

Senior Member
Of course if it was known what the application was or what 'stuff' is to be displayed on the TV then better advice could be given.

The requirements could be from a few square B&W blobs, a few lines of B&W text all the way to full HD multicolour moving videao.
 
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