[quote author="jbeale"]Except that on the original image, I mislabeled it: the USB DATA+ and DATA- wires were reversed. I did not realize it then, since I was only using the +5V and Ground wires. I fixed my own web page about 6 months ago (DATA+ should be GREEN), but it had been up for some time and the damage is done... the old (incorrect) image got copied all over the web (see Google image search below) and when you google for images of "USB wiring", the very first hit is my old, wrong image, on some .ie domain webpage that has no contact info. I'm guessing there's no way to fix this now...[/quote]
Aha, that explains a lot! I was wondering why so many pages on the internet had the colours for DATA+ and DATA- reversed after running into this issue myself... fortunately I spotted the problem fairly early on and double-checked against Wikipedia, which had the correct colour code.
[quote author="ian"]I'm gonna ask about 5volt issues (pic 32 is 3v3), and request PPS on pic32. But mostly I want to ask why they're freeloading on open source, but keeping their special sauce to themselves ;) https://github.com/chipKIT32/chipKIT32- ... icense.txt[/quote]
Yeah, especially since as far as anyone can tell the compiler is basically a rebranded version of gcc-mips with copy protection added that disables optimisation levels above -O1 unless you fork out lots of money to Microchip. (Yes, this includes the standard optimisations developed by the GCC developers, including platform-independent ones.)
[quote author="tcmichals"]The issue is not the gcc compiler, it is the PCI32 libraries, I was changing them to use standard gcc pragma's etc.[/quote]
That's my understanding of the problem too - as soon as you modify or even just recompile the gcc source they provide, you're not allowed to use their PIC32 libraries with that compiler. Nice end run around open source there.
(Not even going to bother asking a question; I'm sure Ian will do his best to quiz them about this.)
[quote author="sqkybeaver"]Linux needs a few MB ram to run, removing the external sram would also remove the capability of running Linux.[/quote]
For what it's worth, the official Atmel SAM-BA client for accessing the ROM bootloader over USB or serial also requires a board with SDRAM. (In fact, if you want to use it with a board that has a different RAM chip to the offical dev boards you need to modify and recompile the ARM code it uses to initialise the SDRAM controller. Not terribly difficult, though the documentation is a bit sparse. Same's true if you use a different main crystal.)
Also, I think your choice of crystal frequency might prevent the ROM bootloader being accessible over USB, if I'm reading this right. Is that a crystal of exactly 28 MHz or a 28.224MHz one? I never fully managed to understand that part of the datasheet and how to determine if the main oscillator is bypassed or not though.
