[M100] Tandy Portable Disk Drive 2

Hello. Received a drive from ebay yesterday and it needed some fixing, wouldn't take in a floppy (fixed) but kept getting a "Drive not Ready" after I tested it again. So I popped the hood again and the belt was melted. I cleaned the belt wheels and put in a new belt; hoped this fixed it but nope

Re: [M100] Tandy Portable Disk Drive 2

hi, just a few questions- Do you hear any activity at all, like the disk spinning? Any LED activity at all? When you toggle power on/off, does the LED flicker once? Are you using battery or external power? Would be good to confirm the internal power supply is getting power and working correctly.

Re: [M100] Tandy Portable Disk Drive 2

Are you using the correct bootstrap? (Pdd 1 vs pdd 2) I made a video a few years ago showing various failure modes if that helps. https://youtu.be/p4q6pqPSaCU On Mon, Nov 14, 2022, 07:27 Stephen Adolph wrote: > hi, just a few questions- > > Do you hear any activity at all, like the disk spinni

Re: [M100] Tandy Portable Disk Drive 2

Not sure if the TPDD2 model has dip switches, but perhaps they're in the wrong setting? On Mon, Nov 14, 2022 at 8:34 AM Josh Malone wrote: > Are you using the correct bootstrap? (Pdd 1 vs pdd 2) > > I made a video a few years ago showing various failure modes if that helps. > > https://youtu.be/

Re: [M100] Tandy Portable Disk Drive 2

At first glance I didn't see any, but could be. I usually fix the obvious first then go back in if necessary - like doctors. Ha. I've got the manual but not a service guide. Thanks. Sent from Yahoo Mail on Android On Mon, Nov 14, 2022 at 11:42 AM, Charlie Hoey wrote: Not sure if the TPDD

Re: [M100] Tandy Portable Disk Drive 2

Yes indeed. TPDD2 does have a little cover for the DIP switch. Just flip it over, it's just the other side from the battery compartment. God Bless, GregS <>< Nov 14, 2022 9:42:45 AM Charlie Hoey : > Not sure if the TPDD2 model has dip switches, but perhaps they're in the > wrong setting?

Re: [M100] Tandy Portable Disk Drive 2

On Mon, Nov 14, 2022 at 11:17 AM Greg Swallow wrote: > Yes indeed. TPDD2 does have a little cover for the DIP switch. Just flip > it over, it's just the other side from the battery compartment. > > God Bless, > > GregS <>< > > > That's my recollection too, that there's a cover. But is there actua

Re: [M100] Tandy Portable Disk Drive 2

Oh my. Checked for cover and assumed DIP under it as the TPDD1 I once had. Opened the TPPD2 lid to expose bright shiney shield. No DIP switches. Never had to change anything so never opened it before now. God Bless, GregS <>< Sent from my iPad > On Nov 14, 2022, at 12:36 PM, John R. Hogerhuis

Re: [M100] Tandy Portable Disk Drive 2

On Mon, Nov 14, 2022 at 11:59 AM Greg Swallow wrote: > Oh my. Checked for cover and assumed DIP under it as the TPDD1 I once had. > Opened the TPPD2 lid to expose bright shiney shield. No DIP switches. Never > had to change anything so never opened it before now. > > And my recollection is that m

Re: [M100] Tandy Portable Disk Drive 2

Hmm that's funny. I always wondered why is there a cover there with nothing!  ;-) Now I know. On Monday, November 14, 2022 at 02:59:19 PM EST, Greg Swallow wrote: Oh my. Checked for cover and assumed DIP under it as the TPDD1 I once had. Opened the TPPD2 lid to expose bright shiney sh

Re: [M100] Tandy Portable Disk Drive 2

Ok I popped the hood and YES there is a dip block of four switches and all are off, and yes it's covered by the shield so opening that little door shows just the shiled. If anyone knows how they should be please let me know. Something I did find was the power supply has a white connector that p

Re: [M100] Tandy Portable Disk Drive 2

Found nothing of value when I looked again. I found that on some earlier models (so it appears) it had a physical dip block, but on later models it had four jumpers on SW1 but were soldered (or etched in the board) at the factory and the bottom part of the four switches showed the contacts as o

Re: [M100] Tandy Portable Disk Drive 2

Sorry folks for all the chatter on this. This is my last email on this. If I find a fix I'll share. I haven't been using the T200s all that long, but learned alot. I also learned that the earlier models did in fact have jumpers and when you opened the little door you saw them. Later models you

Re: [M100] Tandy Portable Disk Drive 2

If you don't mind spending a few bucks, maybe Jeff Birt can look at it for you. On the other hand, there are a few better storage options available these days .. m On Mon, Nov 14, 2022 at 10:47 PM Spencer wrote: > Sorry folks for all the chatter on this. This is my last email on this. If > I fi

Re: [M100] Tandy Portable Disk Drive 2

The operation manual is on-line several places. http://tandy.wiki/TPDD I don't think anyone has ever turned up a service manual or programming manual for it yet. I'm confused by what you said earlier. You said you ran the IPL from ram, but, the boot procedure for TPDD2 doesn't require saving

Re: [M100] Tandy Portable Disk Drive 2

I found this llink (Tandy_Portable_Disk_Drive_Service_Manual_26-3808S_text.pdf (archive.org)) and it says "Service Manual" on the first page. It's not the typical service manuals I've seen. Yes I ran the IPL from Bank1 which was a file I created by following the TPDD2 Operations Manual; within

Re: [M100] Tandy Portable Disk Drive 2

On 11/15/22 20:12, Spencer wrote: I found this llink (Tandy_Portable_Disk_Drive_Service_Manual_26-3808S_text.pdf (archive.org) ) and it says "Servi

Re: [M100] Tandy Portable Disk Drive 2

VERY interesting!  You may have hit on something I'll look into.  That part you mentioned "black arm or the little microfiber pad or the metal part that raises and lowers the arm" makes me think it could be that. Why do I say this?  The first problem I had to remedy was when I first tried to in

Re: [M100] Tandy Portable Disk Drive 2

What can I say, buy now, I am simply clairvoyant. haha People ask for more info but that's for beginners. All I need to hear is where you eat lunch and I can tell you it's from the kickback spikes on the power lines from the large electric motors in a factory elsewhere in your office building.

Re: [M100] Tandy Portable Disk Drive 2

Thanks for your suggestions and time Bruce! Spencer On Wednesday, November 16, 2022 at 05:17:31 PM EST, Brian K. White wrote: What can I say, buy now, I am simply clairvoyant. haha People ask for more info but that's for beginners. All I need to hear is where you eat lunch and I can t

Re: [M100] Tandy Portable Disk Drive 2

"He's Brian, and so's his wife!" - I think Bruce was in charge of the sheep dip. On 17/11/22 12:06, Spencer wrote: Thanks for your suggestions and time Bruce! Spencer On Wednesday, November 16, 2022 at 05:17:31 PM EST, Brian K. White wrote:

Re: [M100] Tandy Portable Disk Drive 2

LOL You could not ask for a more Australian response :-) Regards,Bert On 11/16/22 23:24, Daryl Tester wrote: "He's Brian, and so's his wife!" - I think Bruce was in charge of the sheep dip. On 17/11/22 12:06, Spencer wrote: Thanks for your suggestions and time Bruce! Spencer On Wednes

Re: [M100] Tandy Portable Disk Drive 2

yeah typo. I must have been thinking of a Bruce White I used to work with. On Thursday, November 17, 2022 at 12:52:56 AM EST, Daryl Tester wrote: "He's Brian, and so's his wife!" - I think Bruce was in charge of the sheep dip. On 17/11/22 12:06, Spencer wrote: > Thanks for your sugge

Re: [M100] Tandy Portable Disk Drive 2

And what was I thinking when I wrote "buy now" ? a used car? haha -- bkw On 11/17/22 10:56, Spencer wrote: yeah typo. I must have been thinking of a Bruce White I used to work with. On Thursday, November 17, 2022 at 12:52:56 AM EST, Daryl Tester wrote: "He's Brian, and so's his wife!" -

Re: [M100] Tandy Portable Disk Drive 2

lol. I needed a smile today. Everybody makes an occasional typo, well most anyway. Oh I meant to say Brian not Bruce. I worked with a Bruce White for twenty years and he was alot like you: super-hacker etc. When I needed technical advisement I went to him first. Spencer On Thursday, Novembe

Re: [M100] Tandy Portable Disk Drive 2

Does everybody want to hear a funny???  Guess what?  After reading links from Brian (not the sheep dip guy Bruce) I realized there is a BIG difference with the TPPD1 and the TPPD2. IT ACTUALLY says Portable Disk Drive for TPPD1 and Portable Disk Drive 2 for TPPD2 right on the face!  What about

Re: [M100] Tandy Portable Disk Drive 2

Well that would be good news I think. Question- * did you try to load up TEENY.CO? If you can get that running, it can work with TPDD directly without needing the Utility disk. If you transfer this attached TEENY.DO to your laptop via serial transfer, Then load and run in BASIC, You will get TEE

Re: [M100] Tandy Portable Disk Drive 2

I'll look into teeny, but first I want to see if I can work out using TS-DOS with my TpDD1. Now when I try to format a new disk it fails with Communication Error. Eh one frustration after another. On Saturday, November 19, 2022 at 07:22:37 PM EST, Stephen Adolph wrote: Well that would

Re: [M100] Tandy Portable Disk Drive 2, but really 1

Yes well, yes, TPDD1 is almost entirely different. There is some overlap, some backwards compatibility from TPDD2 to TPDD1, but you need to be using the TPDD1 version of any and all directions. If Greg is out of TPDD1 util disks, you can create your own with pdd.sh if you want, but you don't n

Re: [M100] Tandy Portable Disk Drive 2, but really 1

I'm starting to make my own :) just need to make them .. i have put some in stock in the meantime had to figure out how to do it with a greaseweazel usb drive interface ..lots of fun Greg On Tue, Nov 22, 2022 at 7:58 PM Brian K. White wrote: > Yes well, yes, TPDD1 is almost entirely different

[M100] Tandy Portable Disk Drive 2 service manual PDF now available.

The TPDD2 service manual in all of its glory... https://archive.org/details/tpdd-2-service-manual Jeff Birt

Re: [M100] Tandy Portable Disk Drive 2 service manual PDF now available.

Wonderful quality scans – thanks Jeff! //Ken S From: M100 on behalf of bir...@soigeneris.com Date: Monday, January 8, 2024 at 12:23 PM To: m...@bitchin100.com Subject: [M100] Tandy Portable Disk Drive 2 service manual PDF now available. The TPDD2 service manual in all of its glory... https

Re: [M100] Tandy Portable Disk Drive 2 service manual PDF now available.

Thanks Jeff, A lot of this looks similar to the TPDD1 with the exception of the sector protocols. Quite a few years ago I wrote some software to copy sectors. It would have been nice to have had this at the time. Great to finally have it. Kurt On Mon, Jan 8, 2024, at 9:22 AM, bir...@soigeneris

Re: [M100] Tandy Portable Disk Drive 2 service manual PDF now available.

Geez, up-front the manual said 128K of RAM! I was thinking one could reprogram the ROM to make it a ram disk for a sec there, but the parts list only shows 2K of SRAM unless I missed something? Anyway, thanks much for the efforts, all! Great stuff. Tim On Mon, Jan 8, 2024, 10:23 wrote: > Th

Re: [M100] Tandy Portable Disk Drive 2 service manual PDF now available.

In LaddieAlpha source, I have the following mystery commands: 14, // $0E 35, // $23 48, // $30 49 // $31 14 /$0E remains a mystery. 23 is Get Version Number...solved! 48 is Read/Write Data in Sector Mode... I guess that was already solved it just didn't matter to Laddie 49 is Read/Write Data to s

Re: [M100] Tandy Portable Disk Drive 2 service manual PDF now available.

I think the 128K or RAM is a typo and should only be 128 bytes. Looking at page 97 (set the data to drive's memory) and page 89 (get the data from the drive's memory), there is only enough room to request 125 bytes at a time. Also from my disassembly of the TPDD1 ROM and the very similar arch

Re: [M100] Tandy Portable Disk Drive 2 service manual PDF now available.

Thanks, I figured it HAD to be a typo, otherwise it would be rather ironic for it to have more than 5x as much RAM as the standard 100 could support. On Mon, Jan 8, 2024, 12:05 Darren Clark wrote: > I think the 128K or RAM is a typo and should only be 128 bytes. Looking at > page 97 (set the dat

Re: [M100] Tandy Portable Disk Drive 2 service manual PDF now available.

Birt, would it be a big deal to render this to somewhat lower fidelity? Or split into multiple files? I'm trying to send it to my kindle scribe through Amazon's service. It's 80Mb... gmail's largest attachment size is 25mb. Supposedly I could send it as a zipped attachment but that only brings it

Re: [M100] Tandy Portable Disk Drive 2 service manual PDF now available.

January 8, 2024 11:24 AM To: m...@bitchin100.com Subject: Re: [M100] Tandy Portable Disk Drive 2 service manual PDF now available. Birt, would it be a big deal to render this to somewhat lower fidelity? Or split into multiple files? I'm trying to send it to my kindle scribe through Amazo

Re: [M100] Tandy Portable Disk Drive 2 service manual PDF now available.

Hello folks — I was able to compress the PDF to about 15mb at 144 psi, medium quality. The compressed file looks good and the detailed bits are quite legible. Might there be a place where I could upload or send the file? Cheers, SB -- Greetings from Steve Baker (he/him/his) “Gravity brings me

Re: [M100] Tandy Portable Disk Drive 2 service manual PDF now available.

If you email it to me jho...@pobox.com I can upload it to a bitchin100 file area and I'll share the link. -- John.

Re: [M100] Tandy Portable Disk Drive 2 service manual PDF now available.

Perfect, thanks Steve. Now I can curl up in bed with the TPDD2 manual on my Kindle Scribe. Hosted at https://bitchin100.com/files/hardware/TPDD2_Service_Manual.pdf -- John. On Mon, Jan 8, 2024 at 11:48 AM Steve Baker wrote: > Greetings! Thanks for the opportunity to send this along — hopefull

Re: [M100] Tandy Portable Disk Drive 2 service manual PDF now available.

I rendered it at 300DPI and OCRd it. When you try to uber compress the file the schematics start to become unreadable. Jeff From: M100 On Behalf Of John R. Hogerhuis Sent: Monday, January 8, 2024 1:24 PM To: m...@bitchin100.com Subject: Re: [M100] Tandy Portable Disk Drive 2 service

Re: [M100] Tandy Portable Disk Drive 2 service manual PDF now available.

On 1/8/24 12:22, bir...@soigeneris.com wrote: The TPDD2 service manual in all of its glory... https://archive.org/details/tpdd-2-service-manual Jeff Birt Oh man awesome. A real reference for the error codes and other software bits...

Re: [M100] Tandy Portable Disk Drive 2 service manual PDF now available.

On 1/8/24 22:37, Brian K. White wrote: Doesn't really answer all questions. What IS the whole memory map that those 4 bytes come from, and what even do those 4 bytes mean? Is there really a larger field that just always happens to be only 4 out of 16 bytes used, or are those 4 bytes all there

Re: [M100] Tandy Portable Disk Drive 2 service manual PDF now available.

The TPDD2 service manual in all of its glory... https://archive.org/details/tpdd-2-service-manual I had previously discovered request formats 0x11 and 0x33 which I just called UNK11 and UNK33, not yet documented anywhere at the time. Both do

Re: [M100] Tandy Portable Disk Drive 2 service manual PDF now available.

Seek/Tell is a community extension to the TPDD file-access-mode protocol // Seek (Ken Pettit's proposal) for random access // file must have been opened in mode 2 or 4 // ZZ, $09, $05, (type: Begin = 1, Current = 2, End = 3), Little Endian 32-bit offset, checksu

Re: [M100] Tandy Portable Disk Drive 2 service manual PDF now available.

On 1/9/24 17:58, John R. Hogerhuis wrote: Seek/Tell is a community extension to the TPDD file-access-mode protocol             // Seek (Ken Pettit's proposal) for random access             // file must have been opened in mode 2 or 4             // ZZ, $09, $05, (type: Begin = 1, Current = 2,

Re: [M100] Tandy Portable Disk Drive 2 - firmware dumping and reverse engineering

TPDD2 firmware dumping - breaking this into a new thread. It would be interesting to see if we can use the command 'Request Block' from page 89 to read the ROM of the CPU... I dumped the ROM of the TPDD1 and got a good start at reverse engineering it and documenting it here https://github.co

Re: [M100] Tandy Portable Disk Drive 2 - firmware dumping and reverse engineering

I happen to have a TPDD2 controller board from a dead drive. Maybe I could figure this out. Steve On Tue, Jan 9, 2024 at 6:55 PM Darren Clark wrote: > TPDD2 firmware dumping - breaking this into a new thread. > > It would be interesting to see if we can use the command 'Request Block' > from pa

Re: [M100] Tandy Portable Disk Drive 2 - firmware dumping and reverse engineering

Absolutely. I've also wanted to dump the roms from all the fb100 clones someday just to see if they're identical or not. They're probably all the same code, but it is possible. By now I have one each of tpdd1 (a few actually), tpdd2, fb100, fdd19, and purple computing d103. So if I could manage t

Re: [M100] Tandy Portable Disk Drive 2 service manual PDF now available.

The TPDD2 service manual in all of its glory... While going through starting to update dl2 with all this new info, I also tried a new (old) DOS I recently found called PAKDOS by James Yi. http://tandy.wiki/TPDD_client:PAKDOS And it tries to use a command 0x47 every time it does a directory li

Re: [M100] Tandy Portable Disk Drive 2 service manual PDF now available.

Curiouser, I added support for request 0x47, including the detail that it only works if dl2 is in strict tpdd1 mode. In default or explicit tpdd2 mode, it ignores the command the same as a real TPDD2 does. When I run with strict tpdd1 emulation, PAKDOS sends the 0x47 status command once per di

Re: [M100] Tandy Portable Disk Drive 2 - firmware dumping and reverse engineering

Oh yeah and we know who wrote it: M.FUTAMURA On Mon, Jan 22, 2024 at 11:21 PM Stephen Adolph wrote: > these look like 6301 opcodes. Maybe this worked. > take a look please when you can. thanks. Steve > > > On Tue, Jan 9, 2024 at 6:55 PM Darren Clark wrote: > >> TPDD2 firmware dumping - breakin

Re: [M100] Tandy Portable Disk Drive 2 - firmware dumping and reverse engineering

these look like 6301 opcodes. Maybe this worked. take a look please when you can. thanks. Steve On Tue, Jan 9, 2024 at 6:55 PM Darren Clark wrote: > TPDD2 firmware dumping - breaking this into a new thread. > > It would be interesting to see if we can use the command 'Request Block' > from pag

Re: [M100] Tandy Portable Disk Drive 2 service manual PDF now available.

Thanks Bert, Already got the belts replaced, but good to be ready for working on my two TPDD2 in the ffuture. GregS <>< Sent from my iPad > On Jan 8, 2024, at 10:23 AM, bir...@soigeneris.com wrote: > >  > The TPDD2 service manual in all of its glory... > > https://archive.org/details/tpdd-2

Re: [M100] Tandy Portable Disk Drive 2 - firmware dumping and reverse engineering

Hello Steve, Looks awesome so far! I've started to manually decompile it and some things are not making sense. The first 3 bytes 0x8e, 0x87, 0xFF do make sense this puts the stack pointer at address 0x87FF, the top of the external RAM. This is good. Normally there is some other houseke

Re: [M100] Tandy Portable Disk Drive 2 - firmware dumping and reverse engineering

Hello Steve, I RDP's into my home system and ran the binary through my decompiler. It looks like there might be an issue with how the ROM was pulled. It's missing a byte every 32 bytes, so I'm getting a lot of invalid opcodes. That could also explain the missing 128 bytes at the end too.

Re: [M100] Tandy Portable Disk Drive 2 - firmware dumping and reverse engineering

Interesting, going down the rabbit hole Futamura is referenced in this patent https://uspto.report/patent/grant/6202001 for an embroidery data creating device for Brother. If I remember correctly the TPDD was originally sourced or is the same as a drive used in a Brother embroiderymachine.

Re: [M100] Tandy Portable Disk Drive 2 - firmware dumping and reverse engineering

It was a first pass attempt. I captured it as 128 blocks of 32 bytes. I'll check that I didn't cut off the file by accident. On Tuesday, January 23, 2024, Darren Clark wrote: > Hello Steve, > > Looks awesome so far! I've started to manually decompile it and some > things are not making se

Re: [M100] Tandy Portable Disk Drive 2 - firmware dumping and reverse engineering

It was a first pass attempt. I captured it as 128 blocks of 32 bytes. Was it On Tuesday, January 23, 2024, Darren Clark wrote: > Hello Steve, > > Looks awesome so far! I've started to manually decompile it and some > things are not making sense. > > The first 3 bytes 0x8e, 0x87, 0xFF do m

Re: [M100] Tandy Portable Disk Drive 2 service manual PDF now available.

I had that thing about request format 0x47 backwards. Tpdd1 ignores 0x47, tpdd2 responds to it, which makes more sense, since it's just like several other commands on tpdd2. Doesn't matter to anyone but just for the record to correct saying it backwards before. bkw On Wed, Jan 10, 2024, 11:49 AM

Re: [M100] Tandy Portable Disk Drive 2 - firmware dumping and reverse engineering

128 more bytes ;) On Tue, Jan 23, 2024 at 3:28 PM Stephen Adolph wrote: > It was a first pass attempt. I captured it as 128 blocks of 32 bytes. > Was it > > On Tuesday, January 23, 2024, Darren Clark wrote: > >> Hello Steve, >> >> Looks awesome so far! I've started to manually decompile i

Re: [M100] Tandy Portable Disk Drive 2 - firmware dumping and reverse engineering

Awesome! Looks a lot better, I just ran it through my decompiler and posted the first pass here: https://github.com/BiggRanger/Tandy_PDD/blob/master/PDD2.ASM There are still some invalid opcodes floating around, I need to dig deeper and see what is going on there. I also see several lookup t

Re: [M100] Tandy Portable Disk Drive 2 - firmware dumping and reverse engineering

I've added a rom_dump command to pdd.sh https://github.com/bkw777/pdd.sh You just say "rom_dump filename" and it dumps the rom to filename as binary. Accepts rom_dump or dump_rom equally. If you don't give a filename, it just prints the hex to the screen. $ pdd rom_dump pdd1_rom.bin Works on

Re: [M100] Tandy Portable Disk Drive 2 - firmware dumping and reverse engineering

Hello Brian, Steve, There is a very limited space in RAM on the TPDD1 to load the dumping program into and I needed to make it as small and usable as possible, and for me it was easier to dump to a formatted HEX output and capture that in a terminal program. I'll poke around and try upd

Re: [M100] Tandy Portable Disk Drive 2 - firmware dumping and reverse engineering

No biggie about the binary output. The script is converting it fine. I thought not having to output ascii hex pairs and the rest of the line formatting, would make the code actually smaller and simpler, and maybe fit all inside the internal 128 bytes allowing to read all of the external 2k.

Re: [M100] Tandy Portable Disk Drive 2 - firmware dumping and reverse engineering

Spent some time digging through the source of the TPDD2 firmware, adding comments, labels, and variable names. It's documented (as far as I got so far) here: https://github.com/BiggRanger/Tandy_PDD/blob/master/PDD2.ASM Doesn't look like any hidden commands exist in the firmware. This is the

Re: [M100] Tandy Portable Disk Drive 2 - firmware dumping and reverse engineering

Thanks Darren. Now that we have the real tpdd firmware I wonder what we can do with it. Some of those variables look tempting, like side and # of tracks. Another question.. it looks like was there a second unpopulated serial port on the drive? Anything in the code on that? P7 is unpopulated and

Re: [M100] Tandy Portable Disk Drive 2 - firmware dumping and reverse engineering

Darren, another question, There are some inputs on pins 30,31,32 (called A13, A12, A11) that correspond to P45, P44, P43 on the HD6301. Port 4 of the HD6301 is hooked up to pins 73.36,35,32,32,30,29,28 for P40-P47. I'll go look at the code, but these 3 inputs are configurable. I wonder what the

Re: [M100] Tandy Portable Disk Drive 2 - firmware dumping and reverse engineering

I'll add some info from your nicely documented code. * A13 value is tested at 0xF1FE, and controls a branch to 0xF1EB; seems to change the way serial data is transmitted. hardware default is to branch. * A12 value is tested at 0xF071, not sure what it does yet. hardware default is to branch. * A1

Re: [M100] Tandy Portable Disk Drive 2 - firmware dumping and reverse engineering

This is great for making the emulators and clients definitive instead of full of mysteries and "here we recite the words lest the gods be angry". Can you see why command 0x11 works as a synonym for 0x33? And why does 0x0F respond with the 0x38 return block? When neither of those are commands. Th

Re: [M100] Tandy Portable Disk Drive 2 - firmware dumping and reverse engineering

The part of the code that picks out the commands is a bit goofy, but I believe it's like this to maintain a standard command set across multiple drives with other added functionality. There is a bit mask for the command, so we're only looking at the lower 6 bits (0x00 to 0x3F). Bit 6 and 7 (6

Re: [M100] Tandy Portable Disk Drive 2 - firmware dumping and reverse engineering

I don't see anything in the code that reads the drive parameter table other than the command to output that data. I'm guessing Brother may have other drives with more capabilities and this is only there to tell the host how the drive is configured. Also I don't see anything for a second serial

Re: [M100] Tandy Portable Disk Drive 2 - firmware dumping and reverse engineering

Nice find! I wasn't looking at port 4 data since I assumed it was all address outputs, but P43, P44, P45 are configured as inputs on the TPDD2 (not on the TPPD1). ;Port4.B0    I/O        Pin37    P40    A8 ;Port4.B1    I/O        Pin36    P41    A9 ;Port4.B2    I/O        Pin35    P42    A10 ;P

Re: [M100] Tandy Portable Disk Drive 2 - firmware dumping and reverse engineering

This doesn't matter but on the TPDD1, if you set the dip switches to OFF ON ON ON, then you can dump the rom at 19200, and in that case I need to add a sleep after each S-record. I added 30ms just based a note for something else somewhere in the service manual that you should wait 25ms to betwe

Re: [M100] Tandy Portable Disk Drive 2 - firmware dumping and reverse engineering

Minor correction. Any commands that get translated to an index higher than 0x13 will return an invalid command, not crash the firmware. This statement is incorrect: "I haven't looked for any other logic that would prevent this, but a command 0x13 to 0x2A (except 0x23), or 0x35 to 0x3F will sel

Re: [M100] Tandy Portable Disk Drive 2 - firmware dumping and reverse engineering

E Sent from my iPad On Jan 28, 2024, at 5:29 PM, Darren Clark wrote:  Minor correction. Any commands that get translated to an index higher than 0x13 will return an invalid command, not crash the firmware. This statement is incorrect: "I haven't looked for any other logic that would preven

Re: [M100] Tandy Portable Disk Drive 2 - firmware dumping and reverse engineering

Sent from my iPad On Jan 28, 2024, at 5:29 PM, Darren Clark wrote:  Minor correction. Any commands that get translated to an index higher than 0x13 will return an invalid command, not crash the firmware. This statement is incorrect: "I haven't looked for any other logic that would prevent