Simplest MMC Interface hardware

This is the right place to discuss on how to implement hardware vsync, adding a VIA or AY chipset, puting multiple roms, or how to design a new flash expansion card.
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ibisum
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Post by ibisum » Fri Feb 26, 2010 11:28 pm

Okay, I have an Arduino Mega+centronics cable that I will try to set up on the weekend .. Now beginning my journey into oriculator drive code, thus to formulate a strategy.

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Post by Xeron » Sat Feb 27, 2010 11:34 am

ibisum wrote:Now beginning my journey into oriculator drive code, thus to formulate a strategy.
If you have any questions, feel free to ask. I'll try and put some better comments into disk.c this week.

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Post by Xeron » Sat Feb 27, 2010 7:08 pm

BTW, if the disk emulator has an ARM core or other processor, you could use most of disk.c from oricutron as it is, i'd imagine.

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Post by ibisum » Tue Mar 09, 2010 11:50 am

Just wanted to give an update on this .. I've been setting up the hardware for this project and haven't made much real progress - yet - on actually doing anything interesting, but I wanted to let you know I have an Arduino Mega now set up with this display:

http://www.4dsystems.com.au/prod.php?id=83

And this SD card interface:

http://www.4dsystems.com.au/prod.php?id=22

.. and I've built the wiring harness to go from the Oric data port to the Mega Data I/O lines.

The advantage to using these modules is that they're pretty much plug and play - the Mega has plenty of UARTs for exactly these sorts of things, and the ability to just stream data commands over the UARTs to each module makes programming pretty simple - no complex display handling to deal with and so on. I'm not sure if loading from SD is going to be fast, but I'm hoping that I'll just be able to pre-select a DSK image using the display (which also has a joystick), load it into RAM on the Mega, and virtualize it over the DATA I/O lines easily enough.

This weekend (next chance I get to hack on this) I'll head into the wonderful Metalab here in Vienna (metalab.at) and use the workbench to get the hardware streamlined - I'm not satisfied with my wire-wrap stuff so I'll make a little custom breadboard shield to hold the display and the SD reader - and then I'll work on getting all the basics going in the Arduino environment: display routines (for debugging/hacking/eventual user interface for selecting DSK images to mount), SD read/write/buffer, and also work on setting up the Arduino Mega Data I/O lines for our needs.

I hope by the early hours of Saturday I'll have at least the ability to see what the Oric is doing on the Data port on bootup and maybe display some little graphs for each of the i/o lines, ROMDIS, IO Ready, etc .. indicating activity as necessary.

Then the next step will be to dig into the real work of emulating a microdisc drive .. I've been studying the Oricutron sources for this, and think I have a pretty good handle on how to get ROMDIS working, and so on .. big question is going to be timing on DATA and ADDRESS lines, but lets discuss that when the time comes to actually do something about it.

Anyway, just a heads up - the hardware is coming together and I'll post pics of the work I do on the weekend.

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Post by Dbug » Tue Mar 09, 2010 12:07 pm

Fancy looking stuff for sure, but does not come cheap!
- $49 for the color screen
- $29 for the card reader
plus I guess the Arduino Mega must not come cheap. That's DeLuxe hardware :)

Kind of a shame that this 0.96" device has more power than the whole Oric.

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Post by Chema » Tue Mar 09, 2010 12:37 pm

Great news!

About it not being cheap, I agree, but it is a kind of prototype I assume. If it works, probably the display could be changed for some kind of text LCD with a couple of buttons, which is not so expensive, I suppose.

All in all, without specific cheap hardware this baby won't never be really cheap.

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Post by ibisum » Tue Mar 09, 2010 4:05 pm

Yeah its not meant to be cheap, just provide me with a decent set of tools to do the debugging and so on .. plus I won't be permanently installing all this on my Oric once its working - just using it as a stepping stone to - perhaps - doing a design based around the ATMega1280 .. there are cheaper solutions to the display/SD card issue, for sure.

This is just lab-bench level gear.. when I'm done with using it for this project, I'm going to turn the whole thing into a MIDI/synth system .. ;)

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Post by Chema » Wed Sep 15, 2010 9:30 pm

Any news on this project? I'd love to hear *any* result... even partial results or problems that appeared.

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Post by JamesD » Thu Sep 16, 2010 12:24 am

ibisum wrote:Just wanted to give an update on this .. I've been setting up the hardware for this project and haven't made much real progress - yet - on actually doing anything interesting, but I wanted to let you know I have an Arduino Mega now set up with this display:

http://www.4dsystems.com.au/prod.php?id=83

And this SD card interface:

http://www.4dsystems.com.au/prod.php?id=22
The CoCo SD interface uses a similar module.

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ibisum
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Post by ibisum » Fri Sep 17, 2010 10:51 am

I've been waiting to get a real disk drive around so that I can compare results with real hardware versus what I'm planning on doing with my rig .. the Telestrat finally arrived today (swoon!) so now I've got something I can accurately compare against, I hope I'll make some new progress in the coming weeks ..

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Post by Godzil » Mon Jun 27, 2011 10:46 am

Symoon wrote:Sedoric is limited by its 2-sectors bitmap size. André C. already pushed its limits to the maximum, unsupported by real floppy disks but fine for emulators use (calling it "Bigdisk"), which is: 2 sides, 101 tracks of 19 sectors. Then the bitmap is fully used.
Do you think that we can activate this using a HxC where there is no such limitation from the real floppy hardware ?

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Post by Dbug » Wed Jun 29, 2011 2:42 am

The HxC still needs to go on the controller board, so I guess the question is to know if the WD chip would accept values like 100 tracks per disk :)

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Post by Godzil » Wed Jun 29, 2011 8:32 am

Dbug wrote:The HxC still needs to go on the controller board, so I guess the question is to know if the WD chip would accept values like 100 tracks per disk :)
It looks like that on Atari and Amiga, their FDC is able to do this, maybe our can do it?

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Post by Symoon » Thu Jun 30, 2011 8:44 pm

I have no idea about real harware + HxC supporting it.
I thought that was more or less what you were testing the other day at the meeting, was I wrong?

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Post by Godzil » Fri Jul 01, 2011 10:21 am

Symoon wrote:I have no idea about real harware + HxC supporting it.
I thought that was more or less what you were testing the other day at the meeting, was I wrong?
We only try 80 track floppy, that is standard HD floppy. anyway if we want to use the remote mode of the HxC, we need to be able to access more than 80 track ;)

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