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Well, as a budding hobbiest, I'm less interested in saving time -- it's a hobby, after all, it's supposed to suck up time.


Yes, I but I'd rather suck up my time doing worthwhile development, not fighting with the processor/compiler/microchips awful datasheets.

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Well, my initial investigation of PICs leads me to believe that the standard MO is to develop your own custom circuit, and just add in whatever PIC you need. If I understand this, you're suggesting that I could just get something like the LPC-H2124, and I'm set to begin the programming part, as opposed to having to piece together a minimal circuit (aside from the leads to the steering wheel controls, to continue my previous example project).


Yes, very few external components are required, a couple of voltage regulators, decoupling caps and a crystal and you're good to go. They're fully integrated microcontrollers. Infact the SAM7 range is easier because they embedded the reset chip & 1.8V regulator inside the device, those ones just require the crystal & 3.3V!

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This would, indeed, make things simpler -- especially since I could then work on a linux machine. (The PIC resources for Linux are a little more scarce than for Windows.)


Yes, and it's free and well supported. Obvious advantage as well is that it's a pretty decent compiler too

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Perhaps I'm underestimating the amount of RAM and FLASH is necessary for simple projects. I'm not, after all, attempting to build an embedded web-server. And smatterings of peripherals, while handy when developing something where you want to give options, seems like a waste of space and resources, when I'm building something for a very specific purpose. (Of course, if you mean that I have the option of choosing boards with different peripherals (whether solo, or in groups), then I suppose I'd agree with that.


I try to run from RAM all the time, the advantage? Unlimited breakpoints. My target processor on the project I'm currently working on at work is a SAM7S128, but I use a SAM7S256, for the first month or so I was able to debug entirely out of RAM, which made life very easy and very quick.

While having oodles of RAM or FLASH might not seem necessary, when it's effectively coming for free (given the price differences between ARM7/PIC) then there is no reason to dismiss it purely because it's there! You also have to bear in mind that each instruction on the arm consumes 4 bytes (or 2 if you're running in thumb mode).

From memory the AT91SAM7S321 AT91SAM7S64 AT91SAM7S128 AT91SAM7S256 are all pin compatible, so you can make your mind up after the event on what chip and what resources you actually require.

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Perhaps we're looking at different price lists, or I haven't done a sufficient investigation, but it appears that, while the initial outlay will be comparable (PIC + programmer + assorted bits vs. ARM board + jTag), the PIC route is cheaper once you start doing subsequent projects (depending on what the "assorted bits" are, I suppose, and in my case, I have a big drawer full of "assorted bits" that have been awaiting repurposing).


You'll have to enlighten me as to what you mean by "assorted bits"?!

Have fun.

Adrian

Edit: Fixed the 5.5v typo tman spotted


Edited by sn00p (23/03/2006 07:19)