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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recent status

Well, I’ve put a decent number of hours in on the project over the last couple weeks. I’ve mostly been “spinning my wheels” because I haven’t made much progress, but I think I’ve...

basic schematic

I put up a rough schematic of my design.  It’s not perfect, and will be updated in the near future, but if you are interested.
Click the image below for a full size image.

adding more commands

Now that I *think* I’ve got a handle on the reading portion, I’ve been adding a couple more commands. I added support so that the SX knows what cylinder number it is on.  The F and B commands increase and...

a little code review today

While my send UART code has been pretty solid for some time, I’ve always though my receive uart code needed doublechecked and worked on. I spent some time today just going through the code, graphing out some...

current read problems

It seems as though when I have a read problem, its normally minor, and is a single bit error. I notice that the errors have a tendency for 0s to be incorrectly interpreted as 1s. So I get AB instead of 2B, AB instead of...

added version control and another command

I’ve really wanted version control for a long time.  The ability to go back and undo diverse changes across sessions is valuable.  I also feel a little safer and don’t mind doing semi-destructive edits...

SX software progress

Welp, since I fine tuned the PC to very reasonable numbers, I figure a small overhaul of the SX code is in order too. I had somewhat of an epiphany working the on the SX, which I haven’t *really* looked at in...

will put up sample files

I’m going to put up a sample file or two, but I wanted to get the smallest complete group of bytes that I can…. ie like one full sector, etc. So far, I’m just basically streaming bytes, via disk copy...

new design

I took David’s advice, and I rewrote the code last night. Some highlights: 1. ISR is entirely in assembly. Although I haven’t manually counted, it appears to be about 400ns in length. 2. ISR triggers only...

new design on SX software

Welp, I’m having trouble tweaking my existing SX code. If I modify the timing of the current code, I’m getting all garbage output — even adjusting small amounts to one side or the other, produces much...