faulty divmmc please help!

[creed79]

i have a divmmc interface and yesterday it just stopped working, tried different sd cards, different zx spectrums (both grey plus 2 models) and i either get a jumbled coloured mess or a brief flash of the esxdos screen that dosnt even init the sd card before it says esxdos.sys error and resets to the amstrad basic prompt. nmi dosnt do anything. i even thaught maybe the divmmc rom was to blame so pulled it and burned a new one but thats still doing the same. is the cpld dead?

[creed79]

so i tried swapping my cpu in case it was a m1 line issue but still the same.

[Seven.FFF]

You can try cleaning the expansion bus edge connector, in order of increasing desparation:

• alcohol and cotton swab (mild);
• eraser (fairly mild);
• Brasso (not so mild)

And check the polarity key hasn't fallen out and the device is being aligned correctly.

[stupidget]

i have a divmmc interface and yesterday it just stopped working, tried different sd cards, different zx spectrums (both grey plus 2 models) and i either get a jumbled coloured mess or a brief flash of the esxdos screen that dosnt even init the sd card before it says esxdos.sys error and resets to the amstrad basic prompt. nmi dosnt do anything. i even thaught maybe the divmmc rom was to blame so pulled it and burned a new one but thats still doing the same. is the cpld dead?

Does your Speecy boot ok with no Divmmc plugged in? Reason I ask is that I found an old CRT tv in the loft last week and thought I’d test it with my 128. Plugged everything in and I got exactly the same as you, I still get the same even without the Divmmc plugged in.

[creed79]

so i cleaned the expansion port on both spectrums using isoprop and an eraser no change and both spectrums function perfectly with no divmmc connected.

[oO cozy Oo]

You can reflash it from a .tap file if I remember " from the read me txt"

How to (safely) install/upgrade:
--------------------------------

1. Copy esxide.tap/esxmmc.tap/mb03plus.tap (depending on if you have a DivIDE, DivMMC or MB03+, obviously) to your CF/SD/HDD, load it and follow the instructions. Power Off and remove media.
2. Copy the SYS, BIN (and create /TMP if using DivIDE) directories to your CF/SD/HDD.
3. Insert media. Power On. Reset while keeping space pressed to reinit if needed.

Notes:
------

a) If you replace the SYS directory *before* flashing the new ROM, your previous ROM of esxDOS will not boot correctly.
b) Questions? Bugreports? Complaints about lack of LFN/instructions? Ask on the usual places or send an e-mail to: bugs at esxdos dot org

The only other thing is to check all the solder joints for cracks ect...

[creed79]

the flashing procedure is for the epprom on the divmmc not the actual cpld which i am convinced is where the prpblem lies.

[oO cozy Oo]

@creed79
Any luck with your divmmc

[creed79]

nope still stone dead. wanted a way to flash the cpld from the spectrum but it dosnt look like thats do able.

[Seven.FFF]

No you can’t do that, you need a jtag cable and special PC software. What brand of CPLD does it have?

[creed79]

altera max2 i think - i know theres a way to do it with a pi... so might see if i have a spare pi somewhere.

[oO cozy Oo]

That's a shame, good luck with flashing it and post back if it works

[jamesh]

altera max2 i think - i know theres a way to do it with a pi... so might see if i have a spare pi somewhere.

I had to deal with a few CPLDs lately, so I'd say check if you have the actual code/binary to program first. Then check if you can use OpenOCD or old Quartus, v13. If you can, buy a knock-off "USB Blaster" and use it with OpenOCD/Quartus v13. Otherwise, you'll be better off investing in a proper programming tool (waveshare of terasic), but that will set you back roughly £50. And it will save you a lot of headache. At that price point it may be easier to buy a new DivMMC unit, though.

[creed79]

I have a usb blaster and quartus for my Amiga Vampire and ZX sizif 512 machines but the pinout seems different on the divmmc its 5 pins in a row as opposed to the 2 rows of 5 on the usb blaster so i just figured it wasnt compatible! am i wrong? if i remap the pinout to the divmmc will quartus see it?

[jamesh]

the pinout seems different on the divmmc its 5 pins in a row as opposed to the 2 rows of 5 on the usb blaster so i just figured it wasnt compatible!

I think* the physical connector does not matter. As long as you connect TCK/TDO/TMS/TDI/GND/Vref correctly, it should work. But 5 pins means something is not there, the Vref? Basically, if you are able to identify those pins, it should be safe to use them by manually connecting each one to the corresponding pin on the Blaster.

*) the usual fine print: I've managed not not kill any CPLDs yet, but I wouldn't call myself an expert

[oO cozy Oo]

@creed79
Did you manage to fix the divmmc? As I'm stuck with mi e from zaxon the nano SD , black screen or with a 48k I get a copyright symbol white screen only and it's frozen