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Amiga Floppy

inital results on error correction

While I have yet to actually implement the full-scale error correction as I want to, I did some manual tests today. I basically took a track that I was erroring out on, and swapped in 1-bit away values for the bad bytes.  In some cases, it appeared...

keith
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Amiga Floppy

Good news good news. First perfect .adf

Good news indeed! I’ve managed to create a fully functioning .ADF from a floppy.  I matched the output from my hardware/software combination with a “transdisk” output, and it matches exactly. I used...

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Amiga Floppy

Finally had some luck with FPGA board

So I bought an FPGA eval board and a book on Verilog awhile back.  I made some progress learning things, and had some simple things like UARTs, writing to the LCD, and even some small VGA software(hrrrm, maybe I should...

67 views
Amiga Floppy

data rate vs throughput

Although I’m transmitting from the Parallax SX microcontroller to the PC via USB at a data rate of 2mbps, the actual throughput is much less.  First, there is some overhead, namely start and stop bits, which is...

66 views
Amiga Floppy

great performance increases

Today I’ve worked on optimizing the performance of the AFP reader and have made great strides. My original track times were nearly 475ms. This was 300ms reading the actual disk, 125ms transferring, and process...

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Amiga Floppy

minor success at 2:00am

well I’ve got MFM flowing from the PC drive now.  A couple of things: Pins 10 and 14, the pins I’ve been using since last night, appear to be correct. Pin 10 is the motor lead.  Dropping a corresponding SX...

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Amiga Floppy

more success reading valid data!

I created a disk with a textfile called AMIGA on it which contained thousands of “AMIGAAMIGAAMIGA” throughout the entire file. The idea here is that no matter which part I happen to read/decode, I can tell...

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Amiga Floppy

Found another UART timing issue

Ok. A post or two back, I mentioned that I wanted to rework the receive UART because it wasn’t working perfect. I fixed that, and now it’s reliably receiving. I also mentioned that my sending uart code was...

66 views
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Minor problems on techtravels.org email

I recently discovered a problem where email directed to techtravels.org accounts was bouncing. It’s been fixed. If you’ve emailed something over the last couple months and didn’t get a reply, please...

66 views
Amiga Floppy

mid-january status

So here’s where I’m at: I know my memory read and write routines are good.  I calculate a checksum as I’m writing the data, and on the output of that data to the PC, I also calculate the checksum. ...

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Amiga Floppy

On speed optimization

The theoretical limit, assuming 300rpm drives, is 200ms per track. Or 400ms per cylinder, or 32 seconds per disk. Most attempts read slightly more than one track. I read 16,384 bytes, or 262ms worth. Right now, if I...

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