Well, this wasn’t as easy as I first imagined. There are some issues: 1> By the time you’ve detected the 4489 4489, it’s too late to do much about it. This is because I’m writing one bit at a...
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Anatomy of a flux transition
I wanted to put up an image that displays an actual flux transition pulse coming off an amiga floppy disk whose data was encoded in MFM.
CLICK ON THE IMAGE TO DISPLAY A FULL RES VERSION.
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...
Found one issue
Well, within an hour or so of getting my new LogicPort logic analyzer hooked up, I’m at least noticing some symptoms that I haven’t seen before. The drive is putting out(or the logic analyzer and my sx is...
pullups
These are all 2us per division on the scope. Top trace is the actual MFM, bottom trace is the entering and exiting of my ISR. You should see an entry into the ISR for every falling edge, and every ~2us afterwards. 1k...
revisited memory routines
I was looking over my reading and writing routines. Minimums for the fram are Clock high min. 28ns Clock low min. 28ns Data setup min 5ns I write in two places: First, when bits are coming in from the drive, and the ISR...
