Help with C2 + D&N MEM_CM9 board + D13

nama
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Help with C2 + D&N MEM_CM9 board + D13

Post by nama »

Hi all,
I'm looking for some advice and help with getting my C2 with D&N board working as a floppy system.

Presently the C2 works and I have built a Klyball v2.0 D13 board. (I am presently trying to confirm the v2.0 D13 jumper settings with Grant, as they differ a little from the v1.0 D13).
The 502 board has Cegmon and Basic 1 though 4 EPROMs installed.
I'm using the known working Flash Floppy Gotek drive (with sound mod), with known working disk image files.

When I try to boot (D), the head seems to go to track 0 (or that is what the gotek sound mod suggests, as there is a click), but then nothing happens.

I looked at the D&N manual and I have confirmed the jumpers, and using a scope I have confirmed the timing is correct (see attached)
DN.png
DN.png (125.68 KiB) Viewed 10274 times
Anyway, I'm at a loss as to what to test/try next, and was wondering if anyone has any suggestions.

Thanks for listening.

Phil

2P (1mhz 32k) - 502 + 8k + CEGMON + garbage collector fix BASIC, D&N MEM-CM9 + 24k, 540 (mono) [SOLD]
4PMF (2mhz 24k) - 505, 540, 527, D13 + 5.25" + Gotek
Superboard RevD - CEGMON + 610 board 24k + D13
Spares - 3 x 527, 1 x 505, Backplane
lowrybt1
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Location: New York State

Re: Help with C2 + D&N MEM_CM9 board + D13

Post by lowrybt1 »

Phil,

Doesn't the D&N board natively separate data and timing signals? Meaning, having you tried using the D13 set to data separation off/disabled?
C8PDF w. 48K, 2x 520 24K RAM boards and Glitchworks 64K board
OSI 567 Telephony board
Spare 8" drives
Klyball D-13
nama
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Re: Help with C2 + D&N MEM_CM9 board + D13

Post by nama »

That would be embarrassing if it did, but I found this that seems to suggest the separation happens elsewhere...
D&N.png
D&N.png (69.9 KiB) Viewed 10234 times

2P (1mhz 32k) - 502 + 8k + CEGMON + garbage collector fix BASIC, D&N MEM-CM9 + 24k, 540 (mono) [SOLD]
4PMF (2mhz 24k) - 505, 540, 527, D13 + 5.25" + Gotek
Superboard RevD - CEGMON + 610 board 24k + D13
Spares - 3 x 527, 1 x 505, Backplane
dave
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Re: Help with C2 + D&N MEM_CM9 board + D13

Post by dave »

It's hard to say what's going on. There are a lot of variables here. Here are a couple of things that could help direct further checks:

- Try booting with a floppy (if you have one) to eliminate some kind of odd floppy emulator interaction.
- Check the RAM at 2200 to see if anything at all got loaded.
- hook up your logic analyzer to the RX-DATA (U64 pin 2) and RX-CLOCK (U64 pin 9) lines, as well as the stretched clock (pin 5) and data (pin 4) lines on U64, to make sure you're getting a valid bit stream

Good luck,

Dave
nama
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Re: Help with C2 + D&N MEM_CM9 board + D13

Post by nama »

Much thanks Dave,
I was just at a loss on how to proceed. I'll check all those out and post back.

cheers

2P (1mhz 32k) - 502 + 8k + CEGMON + garbage collector fix BASIC, D&N MEM-CM9 + 24k, 540 (mono) [SOLD]
4PMF (2mhz 24k) - 505, 540, 527, D13 + 5.25" + Gotek
Superboard RevD - CEGMON + 610 board 24k + D13
Spares - 3 x 527, 1 x 505, Backplane
nama
Posts: 357
Joined: Wed Mar 30, 2011 9:44 am
Location: New Zealand
Contact:

Re: Help with C2 + D&N MEM_CM9 board + D13

Post by nama »

Hi Dave,
I was able to find some time to test out the things you mentions.

Firstly a 'real' floppy basically exhibits the same symptoms as the gotek. There is a slight noise from what I presume is the head positioning itself at tk0...Then nothing.

I checked memory location 2200 and nothing seems to be written here after pressing 'D'.

Dave, I hooked up the logic analyzer to the pins you suggested. I'm not sure how to interpret these or what to look for, so I took some screen grabs in the hopes it could be help. Do these look like what I should expect?:

This is a reading without having pressed 'D':
1a.png
1a.png (28.5 KiB) Viewed 10146 times
This is a closeup of the same:
1b.png
1b.png (29.37 KiB) Viewed 10146 times
This is after pressing 'D' and using the DATA line as the trigger:
2b.png
2b.png (48.08 KiB) Viewed 10146 times
A closeup of the trigger point:
2a.png
2a.png (29.75 KiB) Viewed 10146 times
Closeup of the block of activity well after the trigger:
2c.png
2c.png (41.91 KiB) Viewed 10146 times
Do these give anyone any thoughts?
Cheers

Phil

2P (1mhz 32k) - 502 + 8k + CEGMON + garbage collector fix BASIC, D&N MEM-CM9 + 24k, 540 (mono) [SOLD]
4PMF (2mhz 24k) - 505, 540, 527, D13 + 5.25" + Gotek
Superboard RevD - CEGMON + 610 board 24k + D13
Spares - 3 x 527, 1 x 505, Backplane
nama
Posts: 357
Joined: Wed Mar 30, 2011 9:44 am
Location: New Zealand
Contact:

Re: Help with C2 + D&N MEM_CM9 board + D13

Post by nama »

Hi all,
Just wondering if anyone has any idea what I should try next?
I have to tools (O-Scope, Logic analyser, Logic Probe)...Just don't know what I should be looking for.
Do the logic analyser outputs from my previous post look ok?

Help!...

Phil

2P (1mhz 32k) - 502 + 8k + CEGMON + garbage collector fix BASIC, D&N MEM-CM9 + 24k, 540 (mono) [SOLD]
4PMF (2mhz 24k) - 505, 540, 527, D13 + 5.25" + Gotek
Superboard RevD - CEGMON + 610 board 24k + D13
Spares - 3 x 527, 1 x 505, Backplane
dave
Site Admin
Posts: 710
Joined: Tue Sep 09, 2008 5:24 am

Re: Help with C2 + D&N MEM_CM9 board + D13

Post by dave »

Hi Phil,

Sorry, I missed this post. So, if you tried a regular floppy and the gotek, and both work with your C4, but not the C2, then we can presume it's not the disk. If you're using the same data separator and cable, then it's not likely any of those.

Aside from that, if the 6502 chip is OK, then all that's left is the 6850 ACIA, the 6821 for controlling the stepper, and the pulse stretching circuts to make sure valid data is present at the clock edge (and the address decodes for the 6850 and 6821).

Are you seeing pulsed activity on the select lines for the ACIA and PIA when you select "D"?

Is the TK0 line being pulled low to indicate track 0?

If it's not the 6821 or 6850, then I'd like to see more of a close up of the 4 lines you measured. The following order would make them easier to interpret: SEP CLOCK (U64 Pin 2), Stretched clock (U64, pin 4), stretched Data (UU64, pin 5), and SEP Data (U64, Pin 9).

Best of luck,

Dave
nama
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Re: Help with C2 + D&N MEM_CM9 board + D13

Post by nama »

Awesome Dave,
Thanks for the help.
I'll check out all your suggestions and post back asap.

Cheers

Philip

2P (1mhz 32k) - 502 + 8k + CEGMON + garbage collector fix BASIC, D&N MEM-CM9 + 24k, 540 (mono) [SOLD]
4PMF (2mhz 24k) - 505, 540, 527, D13 + 5.25" + Gotek
Superboard RevD - CEGMON + 610 board 24k + D13
Spares - 3 x 527, 1 x 505, Backplane
dave
Site Admin
Posts: 710
Joined: Tue Sep 09, 2008 5:24 am

Re: Help with C2 + D&N MEM_CM9 board + D13

Post by dave »

Also, as you make the measurements, it might be helpful to compare against your C4. Or, take a look at the SAMS C4P manual on the site. The schematics are a bit chopped up, but it has some service hints and reference waveforms.
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