Yet another Microdrive emulator...

For experts to discuss very technical stuff and newbies to ask why the Spectrum they bought off ebay doesn't work.
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xelalex
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Yet another Microdrive emulator...

Post by xelalex » Sat Mar 17, 2018 6:22 pm

Hi there,

I just got a prototype of a Microdrive emulator working. I know, there are a few solutions already out there, and while those are great, I wanted to approach things from a slightly different angle: Instead of using something like an SD card for storage, data is served directly from a PC. So this emulator is actually more of a protocol converter. The advantages I see:

Usability:

- By managing the Microdrives and images on the PC side, I can get a better user interface.

- I don't need to transfer cartridge images to/from a storage card. So for example, I can download an image, right click and choose the Microdrive slot. Then on the Spectrum just do LOAD.

- I can get automated backups of cartridge images, i.e. keep the last x versions of an image to revert accidental writes & formatting.


Transparency:

Now this one is certainly opinionated and debatable, but I wanted to keep things "historically correct". On the Sinclair side, operating the emulated Microdrives should feel exactly the same as using the real thing (minus the unreliability, but some flakiness could be added in the software ;-) So hooking into the Sinclair ROM and providing new functionality was not what I wanted. The emulation should be totally transparent, also to provide maximum compatibility with existing software.


I'm quite happy with the reliability of the prototype. I recently discussed this approach and got somewhat reserved feedback. In particular, the fact that you would need to keep your Sinclair hooked up to the PC was considered uncool. I'm wondering whether that's really such a drawback. I'm looking into using a phone as the host, which could maybe alleviate this concern.

So what do you think? Worth pursuing any further? Is there any need for this kind of emulator? Once this graduates from the prototyping stage, I would consider getting the adapter manufactured. BTW, this should also work with a QL. Trying that out is right next on my TODO list.

Alex
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RMartins
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Re: Yet another Microdrive emulator...

Post by RMartins » Sat Mar 17, 2018 7:52 pm

This is really interesting, specially, if it runs fatefully to the original.
Nice work,

Can you share any pictures of the prototype ?

If the prototype, uses Bluetooth or similar, it would be much easier to use, since there are no wires, and bluetooth is available everywhere, mobile, PC, etc...
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xelalex
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Re: Yet another Microdrive emulator...

Post by xelalex » Sat Mar 17, 2018 9:58 pm

Here's a picture of of prototypes I and II. It's really just an Arduino Nano with an edge connector.

Image

I put this into a box for protection. It's much larger than what it should be, but at least it's Spectrum black ;-) In the end I'd like this to be just a plug.

Image

I'll experiment with Bluetooth, but I need a steady 1Mbit/s serial connection. Not sure whether that can be obtained with Bluetooth.
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xelalex
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Re: Yet another Microdrive emulator...

Post by xelalex » Sat Mar 17, 2018 10:28 pm

And here it is in action :)
Image
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Nomad
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Re: Yet another Microdrive emulator...

Post by Nomad » Sun Mar 18, 2018 3:56 am

Nice work! Good to see the microdrive getting some sweet luvin'
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xelalex
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Re: Yet another Microdrive emulator...

Post by xelalex » Sun Mar 18, 2018 10:24 am

Here's a video of loading the demo cartridge. I placed the console over the video grabber window, so you can see what's going on in the Microdrive daemon. Every 'g' is a 'get sector'.

https://www.dropbox.com/s/gsai8cj11aayp ... o.mp4?dl=0

Image

Would that time-wise be comparable to loading from a real Microdrive? I actually don't have a Microdrive myself. Do the s/w emulators behave truthfully when loading from Microdrive? If so, I could use that to compare.
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