Recent content by migry

In order to make things easier to view I only requested for two sectors to be formatted and then I could shorten the index to index pulse time. After sending the format command byte and 5 parameters, the FDC waits for the next index pulse before starting the format data stream. Zoom in on...

I have been playing some more. It is a case of two steps forward one step back :) . So I abandoned the Teensy3.5/uPD765 breadboard and decided to plough on with the ATmega128/ISA card approach (pictured previously). I started to make some progress and got SPECIFY and SEEK commands to work...

It's an impressive project and congratulations for the creation of the PCB. I have my own 8088 project, only partly completed, and I also decided to go with static RAMs. It just makes more sense. From the "Breadboarding Labs" YouTube channel, whose design follows the Kiselev design quite...

I do have another floppy disk controller PCB with the same single in line pinout, however I have yet to populate it. It uses a WD2729, probably because I had one in my junk box. This one was intended to be used with a MC68000 CPU card. I had hoped to port EMUTOS to this system.

I have temporarily abandoned the uPD765 on the T3.5, and I have gone back to the Multi-I/O ISA card connected to the Arduino Atmel ATmega128. Having fixed a couple of stupid bugs, I am making good progress. I can now change (step) settings using the SPECIFY command, and I can RECALIBRATE (seek...

I meant it as tongue-in-cheek. I don't think adding to my CV will help me get a new job!

Hello @1ST1. My Atari ST disks were from the 80's. They contained source code which I wanted to recover. I also was looking for any Lattice C and Pascal compiler binaries, a set of packages I had at the time. I only have one old PC which has a floppy, a Dell running Win XP. It did read some...

Sorry I might have made some confusion. The board is just showing one which I made for my 8088 system, which did read at least the boot sector from a DD DOS boot disk. It shows the 3rd upD765 device which I have in my collection. I did say that this is another option for experimentation. The...

Well I can't rule anything out. Could indeed be power related, but... As I mentioned the uPD765 is now being powered from the Rigol PSU. A digital voltage monitor across the power rails of the uPD475 measures "5.04V". PSU indicates a current draw of 140mA (now using device no. 3 - shown above)...

Although I am probably wasting my time on a project that has little value, I have continued to work on it and I have made some progress, but just found more different issues. So initially the Teensy 3.5 (T3.5) and NEC uPD765 were plugged into the same breadboard and both powered from the USB...

When I the above I realised that my spreadsheet is wrong. I will correct it for the 5.25"inch once I have researched it a bit more, but anyone feel free to correct the spreadsheet. I will edit and re-upload once corrected.

So as I mentioned another way to experiment was to use a genuine floppy disk controller ISA card. Turns out I already have a non-standard Atmel ATmega128 dev board already wired to an ISA breakout backplane, which I used to debug an ISA card which I designed quite some time ago. I have a...

I'm using 1ms for the reset pulse length, but I've tried other values too. When I was uploading different versions of the sketch I was seeing different values. At least one time I did see 0x80. Currently I am seeing 0x00. It's such a basic initial operation, that I am puzzled as to what I am...

I just posted, having not seen your reply, showing the same waveforms.

Thank you. That makes sense. Yes the documentation is confusing in that often the uPD765 datasheet and compatibles speak about 8" drives. Also some compatible chips have an input pin "MINI" which I assume switches between rates (i.e. density). I didn't clarify this. I am only interested in...