AtoMMCv3 What the fecking hell am I doing wrong

[Prime]

Right I'm pulling my hair out here, I have a respun version of the AtoMMC v3 hardware :

Schematic :

atommc3-th-eagle7.pdf

Schematic

(54.4 KiB) Downloaded 9 times

Firmware :

binaries.zip

AtoMMCv3 files

(17.23 KiB) Downloaded 6 times

I've built the hardware and programmed to boot loader to the PIC, but no matter what I do I can't get the fecking thing to bootload.

My fuses are :

Fuses

I've also tried a couple of SD cards (both formatted FAT 16), one with a 64MB partition, one just the full card. Neither work.
I've named the firmware ATOMMCV3.BIN (all caps), on the card.

Symptoms are, activity LED comes on and stays on, I've hit reset a couple of times as I know it sometimes needs a couple of resets to 'see' the card.

WTF could be wrong?

Could someone take me through the exact process I need to do to get this to work?

Cheers.

Phill.

[roland]

I never use the boot loader, I just program the complete firmware into the PIC. Here's a link to the firmware that I use in my AtoMMC boards: https://site.acornatom.nl/download/mmc4 ... rmware.bin

Does this get you getting started with your respun version?

[KenLowe]

My goodness, this is all very confusing!

From what I can tell, your board is basically a V2 board as shown here:

https://www.acornatom.nl/sites/atomrevi ... mmmc2.html

There's a link at the bottom of that page to the schematic:

https://www.acornatom.nl/sites/atomrevi ... schema.pdf

Edit: Hmm. It looks like the above link is NOT the schematic for a V2 board, but for a V3 board instead! See hoglets post here. So I do now think it's accurate to refer to your board as V3. But the rest of this post is still accurate for the board revision that you have...

Basically, your board has MOSI on pin 24 wired to SD card pin 2, MISO on pin 23 wired to SD card pin 7 and IRQ on pin 26.

I had a need to reflash the PIC on my SirMorris AtoMMC (with exactly the same pinout) recently, and couldn't get any of the available online firmware files to work for me. In the end hoglet created a custom firmware (called 3minus) for me to match the above pinout. This was given the version number 2E.

I subsequently created my own build environment so I could build my own firmware. I was then able to build my own 2E version of the firmware. Using newer source code (that uses faster hardware SPI on the PIC instead of slower bit banging to read / write the SD card), I was then able to build a newer version of firmware, and gave it the version number 2F. These are attached (along with the boot loader) for your info.

Your fuses all look fine, BTW, and you do need to use a small partition when writing the firmware.

Edit 2: Also, what model of PIC are you using? I've been using the PIC18F4525 as that's what was supplied on my original SirMorris board, and I suspect this is the PIC that's used on most boards, regardless of what's shown on the schematic. For reference, this is the schematic for my combo AtoMMC / Econet board (which uses the same PIC18F4525, but has IRQ on pin 6 instead of Pin 26, so uses a slightly different firmware to that attached):

https://github.com/kgl2001/Atom_Econet_ ... AtoMMC.pdf

I'm pretty sure the firmware is built for that specific version of PIC. I think that's why there's a 25 in the filename of some versions of the firmware. I have also seen firmware versions 20 & 23, which I think relate to PIC18F4520 & PIC18F4523 respectively.

If you're trying to use a different PIC (eg the PIC16F874P that's shown on the schematic), then I suspect you may need to build a different version of the firmware. But I'm not certain about that.