FPGA eval board

One of these arrived today.  Very cool.  I’ve only done minor things with it so far — but I’m learning.

I’ve got FPGAs by Example for Verilog coming within a couple days.  Looks like a good book.

The only thing I’ve managed to do so far was modify the assembly for the picoblaze microcontroller to change the text scrolling on the lcd — you’ve got to start some place.

So is this amiga floppy project rev 3 now? heh. I dunno.

(I want to get the afp stable, working perfectly, and move on — I’ve spent too much time on it already, although I’ve enjoyed every minute)

About the author

keith

Amateur Electronics Design Engineer and Hacker

5 Comments

  • I’d love to understand where AFP is currently, I have seen the overview, but reading the chronological logs makes it difficult to understand just how far you have got 🙂 Could you post a summary at some point?

  • Andy,

    Thanks for the comment.

    I know trying to fish through the logs to find the status is tough.

    I was always looking for a pretty status bar graph type of thing for the project.

    I’ll post later this weekend when I have more time, but suffice to say that the AFP reads low density amiga floppy disks reliably and stores them in ADF. Windows only. No HD disk support or write support.

    I have to finish up a new transfer routine because the old one was too unreliable. It required a fair number of different changes, but gives the ability the re-transmit an individual block — which was not possible prior to these changes. I have this routine finished on paper, and I have done a lot of code tracing on it — so I think it’s ok.

    Thanks.

  • Hi. I’ve been reading about your project as I find it interesting.

    Do you have a link to one of your blogposts where you explain how you physically lure the data out of the floppy? I have read Tomi Engdahl’s tutorial on stepper motors in floppy drives, I have been trying his guide in various ways, like tying motor on / disk select / direction etc to Vdd and then pulsing the step-pin on the floppy, but I can’t even get the motor to spin so I have no clue how to play with it.

  • Hi Rikard,

    Don’t let the unused pins float. The drive won’t read output read data if you do. It’s been a little while and I’m starting to forget some of the low level details.

    I think the biggest gotcha was the “write gate.” You’ve got to have that tied to +5v. Is it active low? yeah, I think. So tie it high.

    select first.
    then motor on.
    I’d also tie direction and head one way or the other.

    you can easily step like the way you are saying. but no need to step to get the drive running.

    Look for the light and motor spinning. If you’ve got both, pin 2 will be going crazy. 🙂

    Oh yeah pin 10/12 and 14/16 are sometimes reversed. Depends on the drive. Goofy that they are labeled differently depending on the drive. try a couple combinations until you figure out how the drive works.

    I hope this helps. write back if it doesn’t.

    good luck

  • Oh and one other thing!

    Make sure you have a 1k pull-up resistor connecting pin 2 to +5v. it is an open collector output and requires it!