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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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Latest articles

Amiga Floppy

proof of concept works

Today is the first day in months that I’ve made what I consider good progress. I am now able to read any track(so far) off of any disk with 100% success including checking and relying on the checksums. I read...

60 views
Amiga Floppy

AFP 0.2 WIP SX code

I’ve put some work into cleaning up the SX code tonight. I’ve removed some code sections no longer needed, and added documentation where it was lacking. Code should be commented pretty good. I’ve also...

60 views
Amiga Floppy

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...

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Amiga-VSCInactive

on memory controller optimization

So I’ve been trying to optimize a freeware memory controller for my particular memory chip. I’m running into this situation where the DRAM to ALTRAM copy takes upwards of 24us per line. But I only have a...

60 views
Amiga Floppy

first two bytes of checksum bad

Despite the data being received 100% correct, the data checksum fails in certain cases. It’s always the first two bytes of the 4-byte, 32-bit checksum that are wrong.  The last two are always right.  What does...

59 views
Amiga Floppy

changed from rxtx to jd2xx

Okey dokey. I’ve changed from rxtx to jd2xx.  rxtx didn’t support DTR/DSR flow control, which really is an absolute must for my application.  There would have to be hardware changes that I’d be...

58 views
Amiga Floppy

Am I reading MFM wrong?

I’m beginning to think that I don’t fully understand the signalling coming out of the drive. I understand the concepts behind MFM (I think), but the actual application to this project, I’m not so sure...

57 views
Amiga-VSCInactive

video showing current progress

I posted a video to youtube a little while ago showing my progress. It’s a little long winded (surprise surprise for those who read my posts) but it shows basically the framebuffer portion of the hardware working...

57 views
Amiga Floppy

updates with FRAM access

My initial attempts to write to the FRAM used SX/B commands like SHIFTIN and SHIFTOUT. These operated at a slow rate of about 83kbits/s. It did work and functioned as a good test of the hardware setup. Now that...

56 views