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Hitting the Wall with PIC Programming

:: EPE Chat Zone ­:: ­Radio Bygones Message Board :: » EPE Forum Archives 2010 - » Archive through 12 October, 2012 » Hitting the Wall with PIC Programming « Previous Next »

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brian
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Posted on Tuesday, 11 September, 2012 - 09:59 pm:   Edit Post Delete Post Print Post    Move Post (Moderator/Admin Only)

You know how people talk about “hitting the wall” during a marathon? Well I have the same problem with PIC programming and wondered if anyone else is in the same position.

Back in 2003, those superb EPE tutorials on PIC programming by the late John Becker opened up whole new areas of the hobby here. My abilities do not match those of some others on this list, but I do feel reasonably competent programming in Assembly, thanks entirely to the “kick-start“ gained from those tutorials.

To make another quantum leap forward, the next major hurdle here is to understand how to implement FFT for audio signals with a dsPIC and a graphics display. I understand the basics (only the basics !) of FFT and am aware that library routines are available. However, it is proving extremely difficult to find any readable guidance on how to get started. The Microchip application notes are very “dry” and a Google search on this topic brings back countless hits that are frankly overwhelming. I have spent literally hours searching without success.

Can anyone on this list offer guidance on a practical way of getting started in this area? I suppose we all have our own pet ideas of what would make a good article for EPE. IMHO, a practical project that explains how to implement FFT on a dsPIC with a graphics display would make a gem of an article...just my 5p worth!

Many thanks in advance for any guidance.

Brian

(Message edited by Brian on 11 September, 2012)

(Message edited by Brian on 11 September, 2012)
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gew
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Posted on Wednesday, 12 September, 2012 - 08:48 pm:   Edit Post Delete Post Print Post    Move Post (Moderator/Admin Only)

Brian, yes i am in the same position and getting to the point of finding another hobby, I think maybe I have skills for electronics, but not programming, the late & great John Becker did say that in an e-mail when I asked for help, I could not see the wood for the trees and I keep "hitting the wall" all the time.

Glen
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brian
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Posted on Wednesday, 12 September, 2012 - 09:21 pm:   Edit Post Delete Post Print Post    Move Post (Moderator/Admin Only)

Thanks for that Glen. Hopefully, you will not give up the hobby altogether but I do know exactly how you feel. Lets hope someone else on this list can suggest a practical way forward.
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dave_g
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Posted on Wednesday, 12 September, 2012 - 10:06 pm:   Edit Post Delete Post Print Post    Move Post (Moderator/Admin Only)

Despite learning C many years ago (Microsoft QuickC, as it was then), I found Microchip turgid.

On CZ I have recommended MikroElektronikas' C compiler, and used it a number of times including in the design of my Working Days Clock (EPE Feb 2010, I think).

The point is small steps; I moved from PIC16F to 18F, but have yet to go to 24F or dsPIC. When I'm ready, I'll go the Mikroelektronika route.

The compiler and libraries are rediculously easy to use, so makes what appears to be a big step quite manageable.
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terrym
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Posted on Thursday, 13 September, 2012 - 03:29 am:   Edit Post Delete Post Print Post    Move Post (Moderator/Admin Only)

Yes, don't give up. I was much the same, couldn't see the obvious and over-thinking things.

As Dave says, small steps. Do the simple things and expand them slowly. Trying to tackle the harder things without learning the basics is the fast lane to disappointment.

Brian, my approach might be to get the display side of things working first. IE, get the display to show graphics of any sort. Display any old picture or graph first, not necessarily anything useful.

Learn to manipulate them until you feel confident coding them. Assembler will be a big task for this, but it is do-able.

As a starting point to the FFT, this may be helpful. It is for the 18F series though. Scroll down to the PICFFT download, near the bottom.

http://alciom.com/en/downloads/free-downloads.html

TM
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brian
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Posted on Thursday, 13 September, 2012 - 10:03 am:   Edit Post Delete Post Print Post    Move Post (Moderator/Admin Only)

Thanks Dave and Terry for your encouragement and advice. I will certainly follow it.

Terry, I have just downloaded that link and extracted the documentation. It looks excellent and exactly what I have been looking for. Maybe...just maybe...this could be the way forward here. I will read it more fully over the next few days. Thank you very much for taking the time to help - it really is appreciated.

All the best,

Brian
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gew
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Posted on Thursday, 13 September, 2012 - 09:37 pm:   Edit Post Delete Post Print Post    Move Post (Moderator/Admin Only)

Many Thanks to you all, I look into Mikroelektronika way forward.

All the best,

Glen
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mikeb
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Posted on Friday, 14 September, 2012 - 01:59 pm:   Edit Post Delete Post Print Post    Move Post (Moderator/Admin Only)

I realise your frustration, we have all been there, but you have to consider your approach.

You are saying something like " I have done a little hill walking and now I would like to have a go at the Eiger".

'Difficult projects' (as I classify this), are a marathon, not a sprint. You need to be the type to slowly chip away at a goal (after all, it is a Winter hobby).

Firstly, you need to build up your skills, making all the silly mistakes that we have all made along the way. You will lose plenty of battles, but do you have the persistence to keep your eye on winning the War?

This is why I like the hobby. Many things are given to us on a plate today; a major aspect of this hobby is to think your way to your goal, using guile, persistence and application.

This hobby is annoying, frustrating and at times very depressing, but when you get to reach your objective there is nothing like it. It took me 1.5 years to get my tobacco tin MP3 player working. I could have bought one for £12. I use it every day and I treasure it.

I have just started my balancing robot project - again – that’s 2 years old and has put so many dents in my desk I have had to stick on a plywood cover. I read about the Kalman filter mathematics for 2 months before setting out for the foothills.

Oh … sorry for the ramble …. some suggestions …
If I am going to tackle a ‘tricky’ job then I slowly immerse myself in the subject – not just Google, but libraries and birthday book requests and yes, actually read the book! Your reference to ‘hours’ on Google should be seen as just the start.

I have several projects running at the same time and when I keep bashing my head against something that persists on not working, I give it a rest – sometimes for weeks. A fresh idea or a new approach always pops into my mind. This Chat Zone has always helped.

It is possible a professional like Mike H or Ian Bell might take an interest on behalf of EPE and start you/us off with an article and a bit of hardware/firmware – drop the editor a line.

These guys make it look easy and have the experience to get experimenters started.

You need a good understanding of C and MPLAB IDE if you are going to experiment with a Microchip library. This is because its not going to work first time and you need to find out why. You need to be able to follow the basic operation of the code and understand what is going on.

I hope this ramble has not put you off.

Rgds

mb
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brian
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Posted on Friday, 14 September, 2012 - 07:52 pm:   Edit Post Delete Post Print Post    Move Post (Moderator/Admin Only)

Thanks for the reply Mike. None of what you have said is "ramble" - just solid advice that does of course make eminent sense.

Well to use your analogy of climbing the Eiger, at least I have already made it to base camp!

Searching for "FFT LCD" on You Tube shows just how many clever people there are around but I guess some must have professional training.

No you have not put me off - but you have added a touch of realism, which is exactly what was required. Once again, thank you - any to everyone else who has replied - for all the advice.

Brian
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terrym
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Posted on Saturday, 15 September, 2012 - 04:48 am:   Edit Post Delete Post Print Post    Move Post (Moderator/Admin Only)

Let us know how you get on Brian.

A running post of all the little (big?) steps you make, the successful and not so, would be useful to others I think.

TM

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