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

[Iesca]

Any plans for a 3D-printed case design for the original Tash20? (With the new breakout board of course.)

 

[tashtari]

"News, everyone!"


Cases with custom front and back plates are now available for TashTwenty Tiny boards! Thanks to @demik 's work, the LED and card holes are positioned perfectly.


TashTwenty Rev 3 kits are now available! The difference with Rev 2 is slight - mainly the board is a different size so that it matches better with the Adafruit SD level shifter, and there's a hole drilled in it for a standoff, which makes the whole assembly feel a lot more secure. (I unfortunately made the hole slightly too small for the standoffs I got, so I'll widen it with a drill before sending them out.) Also, the pullup resistor now connects to the correct voltage pin, even though the pullup resistor is no longer necessary - belt and suspenders.

Firmware 20220621 is out! It contains some minor fixes to the way cards are initialized, hopefully this will take care of any remaining issues with weird cards.

And finally: TashTwenty Tiny kits are out of stock! I'm sorry for introducing cases for a board that's out of stock, the timing kind of sucks. If you're interested in a TashTwenty Tiny kit, please let me know - I'll make more if enough people are interested!

Links:

• Thread posts:
  • How to read TashTwenty blink codes (1704 only)
  • Known-good SD card image with System 6.0.8 and a second partition (1825 and 1704)
  • Known-good SD card image with System 4.1 and a second partition (1704 only)
  • Python tool for making SD card images (1704 only)
• Github:
  • Source code (including PCB stuff)
  • Latest firmware for 1704 (20220621)
  • Latest firmware for 1825 (20211128)
  • Latest gerbers for TashTwenty Tiny and "DB"-19 adapter
• Other:
  • DCD page on the 68kMLA proto-wiki, including compatibility chart

Latest price list:

	Kits:
$17	TashTwenty Tiny by @demik, including ribbon cable (supports full-size SD cards, fits in a Hammond case) (OUT OF STOCK - PLEASE LET ME KNOW IF YOU'RE INTERESTED IN THESE BEING RESTOCKED!)
$17	TashTwenty Rev 3 by me (smaller, less soldering)
	Optional Extras:
$8	Blue translucent Hammond case for TashTwenty Tiny with custom front and back plates
$5	Transcend 4 GB microSD card (known to work, will program with demo image)
	Extra Parts (not necessary if you buy kits):
$1.75	Programmed PIC16F1704
$4	"DB"-19 solder cup connector

Happy HD20ing!

 

[Iesca]

Just wanted to let everyone know that I was able to format a 128MB San Disk card with FAT/MBR in High Sierra, then bring it over to Tiger to reformat the partition as HFS, and it mounted without trouble in the Tash20 on my Mac Plus!

 

[superjer2000]

I just received mine today! Really professional looking kits and I’m excited to put them together!

 

[Iesca]

Any plans for a passthrough on a future revision?

 

[ktkm]

Any plans for a passthrough on a future revision?

Yes, it would be very nice to be able to hook up an extra floppy drive!

 

[Iesca]

Yes, it would be very nice to be able to hook up an extra floppy drive!

My first thought was that it come out the opposite end off the back, but now I'm thinking from the top would be easier to route with its current design? Might not be very structurally sound though, unless you plug in the external floppy first, then the Tash20 into the floppy port.

 

[demik]

Well that was an idea at some point, but there was (female) DB-19 availability issues (and IRL issues)

My first thought was that it come out the opposite end off the back, but now I'm thinking from the top would be easier to route with its current design? Might not be very structurally sound though, unless you plug in the external floppy first, then the Tash20 into the floppy port.

Yeah Tash20 needs to be first, otherwise that will not work. It's not a real passthrough, the PIC in Tash20 will select the floppy drive as well.
I will try a design in a few months if free time is a thing. The design was called "Tiny" because a bigger kit with passthrough is supposed to be a thing at some point.

 

[jajan547]

I’d like to get one of these if I could

 

[Iesca]

Yeah Tash20 needs to be first, otherwise that will not work.

Ah, sorry, that's what I meant, by plugging in the floppy drive into the top of the Tash20, then plugging the Tash20 (with the floppy drive already plugged into it from the top) into the floppy port at the back of the Macintosh.

 

[adzq88]

I'm also interested to get a TashTwenty, or at least programmed chips so I can build mine

 

[adzq88]

Yes, it would be very nice to be able to hook up an extra floppy drive!

Approvable idea!

 

[tashtari]

Aaaand stock of both kits has run out. Hammond cases are still available for anyone who's already built a TashTwenty Tiny, PICs are still available for anyone wanting to do their own build but not having a PIC programmer (and/or finding PIC16F1704s hard to source).

	Kits:
$17	TashTwenty Tiny by @demik, including ribbon cable (supports full-size SD cards, fits in a Hammond case) (OUT OF STOCK)
$17	TashTwenty Rev 3 by me (smaller, less soldering) (OUT OF STOCK)
	Optional Extras:
$8	Blue translucent Hammond case for TashTwenty Tiny with custom front and back plates
$5	Transcend 4 GB microSD card (known to work, will program with demo image)
	Extra Parts (not necessary if you buy kits):
$1.75	Programmed PIC16F1704
$4	"DB"-19 solder cup connector (OUT OF STOCK)

If you're still interested in a kit, please message me and let me know! I'll make more if enough people still want them, but I don't know if you're interested unless you tell me. =D

 

[tashtari]

Actually, I should add to that that I have PCBs for both TashTwenty Tiny and TashTwenty Rev 3, just not parts. If you happen to want just a PCB and a PIC for your own build, I can hook you up, just message me.

 

[superjer2000]

Any tips for troubleshooting a code of 0x05?

I built both TashTwenties and am having the same issue with both - Not recognized by my Mac. I have tried a three different SD cards

I connected the cards to my oscilloscope and both flash b00000101

I am pretty sure it’s still an sd card compatibility issue but if this error code gives any clue it might save some troubleshooting time.
Thanks!!

 

[tashtari]

Any tips for troubleshooting a code of 0x05?

Hmm. 0x05 indicates that the card entered SPI mode okay and responded to a few commands as normal but blew up when we tried to get it to initialize. It sounds like it could be caused by the issue where the card needs an extra 0xFF clocked out to it before every command, I sent you your kits before I'd made that update to the firmware. How do you feel about picking up (no pun intended) a PICkit3? Thanks to the cost of international shipping, sending you updated PICs would cost almost as much...

 

[superjer2000]

Thanks @tashtari I will look into the pickit3. I just ordered some transcend cards from amazon which should be here tomorrow and Wednesday and I’ll try those first.

 

[superjer2000]

Thanks @tashtari I will look into the pickit3. I just ordered some transcend cards from amazon which should be here tomorrow and Wednesday and I’ll try those first.

So this is a bit odd...

My Transcend 2GB MicroSD card arrived today.

TashTwenty Rev 2 - Success
I was able to boot my TashTwenty Rev 2 by writing the 1704 image to it linked earlier in this thread.

Demik TashTwenty Tiny - Not yet...
I then put it into the SD Card adapter and tried it in my Demik TashTwenty Tiny and no dice, so I connected my oscilloscope again and was surprised that the debug line just stayed high the whole time, instead of flashing 0x05 like before or something else.

I then swapped out for one of the SD cards that wasn't working yesterday and once again saw the 0x05.

Put the Transcend 2GB card and adapter back in and the debug line again remained high.

So I tried putting the Transcend 2GB card into other SD card adapters, including the one where I was getting the 0x05 error but in each case, the debug stays high whenever the Transcend 2GB card is installed, so it seems like the firmware doesn't like something about the 1704 image and is freezing.

I had earlier tried to make my own blank image but didn't have any luck - Specifically I used fdisk on my linux box to:

1) Delete any pre-existing partition
2) Create a new primary partition 20MB in size starting at sector 2048
3) Change the type of 0xAF
4) Write the partition

Is this the right way to do it? EDIT: Making the partition this way did work - with TashTwenty Rev 2 (although I used 19MB) but not with my Demik which seems to have an issue with the Transcend microsd card.

Thanks!!

 

[tashtari]

the debug line just stayed high the whole time, instead of flashing 0x05 like before or something else.

That's very strange - no response from the !CS line at all, not even to try to initialize the SD card? My first thought is to try swapping the PICs from one to the other - if the failure follows the board, maybe there's an issue with power; if the failure follows the PIC, then... maybe ESD? It'd be very strange if that were the case, but it's not impossible.

 

[mg.man]

Oh, forgot to share... this is my current preferred method of building the original
View attachment 42375
...the uSD adapter "slung" underneath.

Small update... I have all the bits, but not the time to upgrade my TT 1.0s to 1805s and latest firmware, but I did do some quick testing on a SE/30 I'm restoring with a ROM-inator ROMSIMM. Works great!

@tashtari, I tried both the one pictured above as well as an identical one with the pull up resistor removed (which I'd pulled off when trying to figure out why several of my uSD cards were not working) - the resistor-less one worked fine on the ROM-inated SE/30 as well.

Speaking of uSD cards... I bought some brand new (but chinese-obscure branded - Lerdisk) uSDs off Amazon - in 512Mb and 2Gb capacity. NONE of them work. They format, I can copy files onto them, but they just don't work. FWIW, none of them work on my BlueSCSI either. After hitting problems, I checked out the AMZ feedback. Mostly positive, but quite a few complaints about problems on rPis... So, I don't think this is a TT-specific phenomenon.