[Coco] Help with Nitros9 on SDC?

[michaelkline704 at gmail.com]

Hi Don,

This is just a thought... It may help to point more to the SDC. Do a RUN at 1 command to have it just load DECB instead of the combined SDC command structure. Then boot NITROS and see if you can get it loaded.

Michael
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-----Original Message-----
From: Coco <coco-bounces at maltedmedia.com> On Behalf Of Don Barber
Sent: 12 January 2022 08:35
To: coco at maltedmedia.com
Subject: Re: [Coco] Help with Nitros9 on SDC?

Morning folks,

Pretty sure I've narrowed this down to a bad CocoSDC.

I compiled the StreamTest.asm code from the CocoSDC manual.
When I exec it, I get the same behavior as when I try to load EOU, eg about 5% of the time it works, the rest of the time the machine locks up, resets, shows gibberish on the screen, goes into a weird pmode, or some combination of the above. So something is making the CocoSDC write to the wrong memory address(es). The behavior is the same either with the MPI or direct to the cartridge port.

Any thoughts on if this could be a bad cartridge IO chip inside the coco (I'll admit my ignorance as to the internals), or just a bad CocoSDC?

If anyone has a spare CocoSDC I could borrow (I'll pay shipping both
ways) before I drop $50 on another one, I'd appreciate it. I'm in central Maryland.

Thanks,

Don