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TashTwenty: Single-Chip DCD (Hard Disk 20) Interface

ErinRF

Active member
I’d be interested in a kit of one of these for sure, probably the chip if that’s the only option as well.
 

demik

Well-known member
@tashtari Just tested on my IIcx with a ROM-inator II from @bigmessowires

Works fine from the ROM disk (System 7.1), although only one partition is visible. Cannot test much further because the IIcx cannot boot from a SCSI drive for now.
 

tashtari

Well-known member
I'm betting the one partition is because of that bit of behavior I found recently where if you put more than two chained DCDs on a newer machine (I'm guessing this is true of every machine except the 512 and the Plus) it only recognizes the first.

I've attached a demo SD image that has only two partitions (System 6.0.8 and a blank, formatted drive, both HD20-size) on it to act as a known-good for testing. There are versions of it for the PIC16F1825 and for the PIC16F1704 - the latter is set up to use custom icons and also gets around a tiny issue with the 1825 firmware which I haven't yet fixed (it reports one less sector of capacity to the system than really exists on the card).
 

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demik

Well-known member
Thanks @tashtari !

It's indeed that issue. With your demo image, I have two DCDs now. Can boot 6.0.8 from it. 7.1 works fine as well. 7.5 doesn't, even with the HD20 init, although it's without the ROM-inator, since for some reason my Iicx doesn't want to boot 7.5 with the ROM-inator in.
 

tashtari

Well-known member
Well, I'm getting set up for slightly larger-scale kit-making, I have the PICs, I have the "DB"-19 connectors, I just ordered the PCBs. JLCPCB was so cheap that I had a bunch made of both demik's board and mine.

I don't have final pricing worked out yet but PIC, PCB(s), and "DB"-19 connector sum to about $7, so it'll be that plus the cost of other components, maybe $15 total (pick demik's board or mine, the cost will probably be about the same). Shipping extra, of course.
 

tashtari

Well-known member
Okay, I've got the stuff priced out on Digikey, I was about right with my guess before, so, presenting... the price list!

PriceItem
$15Kit for building TashTwenty Tiny by @demik (takes full-size SD cards, has LEDs, fits in a Hammond case, was designed by someone who knows what he's doing)
$15Kit for building TashTwenty Rev 1 by me (smaller, less soldering)
$5Transcend 4 GB microSD card (known to work, will program with demo image)
$1.75Programmed PIC16F1704 (the kits include one already, this would be extra)
$4"DB"-19 solder cup connector (the kits include one already, this would be extra)

Notes:
  • Shipping is not included. US will probably only be a few bucks extra, we can discuss details.
  • These prices are approximately my cost, this is not a for-profit venture.
  • I haven't received everything I've ordered yet, but get your orders in sooner rather than later, it'll help me plan quantities of certain parts like the SD shifters and the Transcend cards - I won't take payment until I'm ready to ship.
Please Understand (covering my ass):
  • No warranties or guarantees of any kind are provided, no returns, no refunds, no regrets.
  • Kits consist of boards and parts only. They require skilled assembly, including soldering - you should be comfortable with doing this.
  • Firmware should be regarded as experimental. It works for me, I think it'll work for you, but I could be wrong. I've worked in the industry, I know how much testing a really-for-real data storage product goes through, and I know this one hasn't gone through anything as rigorous as all that.
  • Kits should also be regarded as experimental. They have not undergone rigorous testing or quality control, either.
  • Firmware updates may be provided but require the use of a chip programmer (which is not included) that can program the PIC16F1704.
  • Technical support is provided on a best-effort basis, subject to my own time, availability, and sanity.
If you've read all that and you're still interested, send me a direct message and we'll get things rolling. =)
 
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tashtari

Well-known member
Oh, and, just so you know which is which...

TashTwenty Tiny (by @demik):
1651454820386.png

TashTwenty Rev 1 (by me):
1651454835408.png

TashTwenty Rev 1 will be red rather than purple with this new PCB order. Pictures are of the assembled final product, naturally - kits require assembly.
 

mdeverhart

Well-known member
It looks like the TashTwenty Tiny by @demik can be used internally or externally - is that correct? Does it come with the ribbon cable to connect the internal header to the DB-19 board?
 

tashtari

Well-known member
Does it come with the ribbon cable to connect the internal header to the DB-19 board?
Ah, excellent question. It does not come with a ribbon cable.

It can be used internally on certain machines where the secondary drive connector is internal, which I think is just the LC and the IIx. If you are willing to be creative with wiring, you can use it internally on other machines, too - you'd have to connect it to the primary drive connector and then use the J1 jumper to connect it to the !ENBL2 pin on the IWM or SWIM, which would involve clipping or soldering a wire onto a leg of the chip.

Addendum to price list:
PriceItem
$218" 20-conductor IDC ribbon cable for use with TashTwenty Tiny
 
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demik

Well-known member
I'm putting the finishing touches to the case.

Front will be a cheap PCB. The ribbon cable will go by a trimed portion on the back panel (4 blank ones are included with the case)
Possible colors : light gray almost white, translucent blue, black with matching PCBs (white, blue, black)
But you can go wild with the front (yellow / pink / purple / etc) as it's just a PCB or just create one from the blanks if you have a C&C machine.

Example with translucent blue:

TTT_case.jpeg
 

tashtari

Well-known member
You know already that I am interested in some. Where will you ship from?
Colorado, USA. International shipping from the US can be a little spendy. I think I can do First Class International to Europe for about $15-20 but I'm not sure what tracking is like. Priority Mail (which I know is tracked) is a little over $40.
 

micheledipaola

Well-known member
Colorado, USA. International shipping from the US can be a little spendy. I think I can do First Class International to Europe for about $15-20 but I'm not sure what tracking is like. Priority Mail (which I know is tracked) is a little over $40.
Thanks. I would go with first-class and a lot of finger crossed, otherwise really I would spend much more for shipping than for the actual items.
PM on the way :)


Edit:
sorry @tashtari,
now I realized that @demik is shipping from Europe.... so maybe it could be better to ask him directly :D
 

demik

Well-known member
now I realized that @demik is shipping from Europe.... so maybe it could be better to ask him directly :D

Hello, I'm not able to ship anything besides the couple unit I promised to members. I don't have many parts and have no time for more ATM. The other issue I have right now is that EU customs and French IRS are taxing the shit out of me, so a kit from me will cost close to that of a Floppy Emu.

I will let people know when kits will be available :) Thanks all for your interest.
 

dochilli

Well-known member
I have some questions:
1. Where can I download the HEX-files for the firmware for the 1825? I am new to PICs and tried to compile the firmware with MPLAB X IDE but I get an error with the file P16F1825.inc and the build stops.
2. Which IDE and compiler do you use to compile the firmware?
 
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