keith
I hate when this happens. 🙂 The Parallax SX microcontroller line has reached production EOL. The owner of the SX design (www.ubicom.com) has given Parallax final notice that we are to place a lifetime buy of wafers. We...
Histogram of one track
Here’s a histogram of one track off an amiga floppy disk. Notice the peaks near 4us, 6us, and 8us. I’ve got this data from my logic analyzer, crunched through my little C proggie, and then graphed with...
bought a Saleae Logic. Another tool for my toolbox
I bought at Saleae Logic which is an inexpensive logic analyzer. See link here. It isn’t nearly as fast (only samples at 24mhz max), and it doesn’t have as advanced triggering capabilities, but it does do...
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...
got build environment working again, fixed uart code
So awhile ago I bought a quad core machine which runs Vista 64. Once I had the new machine, I tried getting my build environment for the AFP working again. NetBeans, the java IDE I use, has 64-bit support but there...
my checksum algorithm
So I’m using an XOR checksum to detect errors in the transfer between the SX and the PC. I always thought it was a reasonably strong checksum, even though it’s still an 8 bit checksum. I found a neat...
sanding a 556 timer IC to expose the die
So tonight, just for the fun of it, I decided to sand, by hand, a 556 timer IC. I just bought an extremely inexpensive microscope and was very interested to see what pictures I could get from it. Unfortunately, for me...
upgraded Tivo HD serial 652
I followed the instructions at but when I tried to expand the partition after the copy, it failed with the following error: Primary volume header corrupt, trying backup. Secondary volume header corrupt, giving up...
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...
Brian Instruments Brikon 723 Floppy Drive Analyzer
$20 on ebay got me one of these Brian Instruments Brikon 723 Floppy Drive Analyzer Ever since I’ve seen this device mentioned in the datasheet of many different floppy drives, I knew I wanted to get ahold of one. ...
redone transfer routine
So my transfer routine has been a little flaky lately. I’m not sure exactly why but I think it’s related to the number of processes I’m running. While it’s a P4 2.4, I think USB scheduling is...
Canada Post sucks
So I made the mistake of having an Amiga book shipped from Canada using Canada Post Expedited USA shipping. It was dropped off at a post office on Nov. 17th in Mississauga, Ontario. Now Mississauga is about 300 miles...
logic analyzer on Amiga 500 Paula chip
So I’ve attached my Intronix LA1034 to the Paula chip, the 16-bit wide data bus, and the DMA Request line. I triggered the logic analyzer on 0x4489, of course. Here’s the results: (click for a full size...
quick memory check
So on bootup, I now have the hardware do a memory check. I basically take and write out a bunch of values to the memory, and then read them back and make sure they read back properly. The values written are based on...
sleep inversely proportional to the AFP and no more tokens
So I have figured one thing out. The more I work on the AFP, the less I sleep. At least that’s how it’s been over the last two nights. Two nights ago it was 3am, last night it was after 2am. Ideas come and...
new read routine implementation started
Last night, until 3am, I spent redoing my read routine to incorporate the method discussed in the comment of the last post. Basically, I use the time between the pulses as an indication of the data. I store 2-bit...
redesign of read routine
After skimming the patent I referenced in the earlier post, I’m starting to come to the realization that in order to have an effective floppy controller, I need to implement a decent PLL which can better track the...
how the amiga reads floppies
So I’ve forever wondered, at the hardware level, how the amiga reads floppy disks. I’ve gotten bits and pieces over the years, but I’ve never really understood the bulk of it. So there are four main...
