techtravels.org

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...

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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...

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...

Ground issues

Although I’ve been attempting to have a common ground for this whole project — I’m not sure that is going to happen. At least not at this stage of the game. I tried connecting the ground off the floppy...

memory chip mounted

Welp, I got impatient, and went to Radio Shack to buy their soldering station. I still have mine coming in the mail, but its ground from Arizona, which may as well be ground from Alaska. I soldered the header pins onto...

losing data

I’ve been thinking more and more about how exactly I’ve been losing data. It’s alot of data. The worst case I’ve seen is about 140 bytes. This is 1120 bits, or 2240us. This is a LONG time for my...

found bug last night

With this new FPGA solution, certain tracks would result in what I call a “short read.”  A short read is any received track that contains less than 28,125 delta T’s, aka pulse times.  Given a certain...

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...

Current status updated

Current status updated I was originally going to use a Microchip PIC, but they are just too darn slow. I gave up on the idea of using the PIC as a one-chip solution, and tried to use it as just a clock generator feeding...

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...