David Given
ed5b9c0b8d
Implement simple precompensation; it makes HD writes more reliable (still not
...
quite right, though), but seems to mangle DD.
2018-10-13 20:04:52 +02:00
David Given
99e222d012
Change the record mechanism to use an upcounter, not a timer.
2018-10-13 16:54:51 +02:00
David Given
1e7e91c4cd
Intervals of 0x00 are actually 0x100 ticks.
2018-10-13 16:54:17 +02:00
David Given
66cdf0c00c
Always process data in a consistent order.
2018-10-13 16:53:45 +02:00
David Given
aa7d420754
Start work on an autocalibrator to detect precompensation, but something's gone
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wrong and our reads are all bunk.
2018-10-13 12:04:37 +02:00
David Given
b46d55cc07
The USB capture/replay interface now uses timestamps rather than intervals;
...
this makes the hardware considerably simpler and more reliable (as I don't need
to spend time resetting the timers between pulses). Still doesn't help writes,
though. Simplify and improve clock detection; add an abortive attempt at an FM
decoder (turns out that the Brother doesn't use FM).
2018-10-13 01:19:17 +02:00
David Given
333fd989de
Rename decode to mfmdecode now that I've found what might be an FM disk.
2018-10-11 22:52:59 +02:00
David Given
9dcfbc2ab1
More replay timer simplification: more robust?
2018-10-10 23:15:20 +02:00
David Given
5d4e929302
Added the fluxdump command, for exporting a fluxmap into something like
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Audacity where it can be visualised.
2018-10-10 23:02:45 +02:00
David Given
1c0cc1f831
Rewrite the pulse replay logic to be, maybe, more reliable? Add lots of decoder
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debugging.
2018-10-10 22:32:58 +02:00
David Given
1430dfc4e1
Add the test pattern generator back again. Try some experimental code to
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convert a fluxmap into an encoding_buffer, but locking each pulse to a us grid.
I'm not sure whether this is good enough for reliable decoding, but early
indications look promising.
2018-10-09 23:46:24 +02:00
David Given
5bd01d5ebc
Refactor all the raw buffer stuff to be less bad. Add an encoded buffer, which
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will be used for assembling fluxmaps to write to the floppy.
2018-10-09 22:49:10 +02:00
David Given
40b9fbc25d
Fix ghastly DMA ordering bug leading to corrupted writes. Writes are less
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corrupted! Still can't reliably read back what I wrote, though. Added a test
pattern feature to write, to aid debugging.
2018-10-09 00:23:21 +02:00
David Given
443082f3c4
Written my first data --- it's kinda garbled, but there's definitely sectors in
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there!
2018-10-06 23:30:14 +02:00
David Given
30271d7e95
Just enough writing works to utterly destroy tracks now.
2018-10-06 23:01:24 +02:00
David Given
8f1cef48b1
Realise that the weird data dropouts were due to a stray capacitor on the
...
board... so remove it. Better now. Also realise that PSoC Creator lies to you
about clocks, so adjust the sample clock to be derivable from the USB clock,
making it both the right frequency and much more accurate --- decode success is
dramatically improved (presumably due to less jitter). Redesign the capture
logic to use a timer; simpler now.
2018-10-06 18:32:57 +02:00
David Given
74d051dff3
Start sketching out the write code; attempt to make more robust in the face of
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the weird data dropouts.
2018-10-06 13:47:34 +02:00
David Given
bf3e689708
Sketch out the replay logic, although it's not connected to anything yet.
2018-10-05 23:42:32 +02:00
David Given
d6b71beacf
Reduced the sampling rate to 8MHz; 16MHz means that on a 720kB disk some
...
samples are more than 128 ticks apart! Doubled the settling time to make reads
more reliable; added disk change logic to rehome the disk when you replace
floppies.
2018-10-05 22:58:56 +02:00
David Given
5a0229b06f
Rewrite most of the MFM decoder... again. Now it parses the records to find out
...
what they are and how big they are. After lots of tinkering with the clock
code, it now correctly decodes a 720kB floppy into records. Something seems to
have gone wrong with 1.44MB floppy capture, though.
2018-10-05 21:57:24 +02:00
David Given
3276ed785e
Replace the MFM decoder logic with something which very nearly works. Now I
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search for the sync region before each record and recalculate the clock from
that. Unfortunately, knowing when I've reached the end of a record and so
should start resyncing is hard without parsing the records themselves, and so I
frequently lose byte phase between records.
2018-10-04 22:36:36 +02:00
David Given
339cdd5105
Add a partially working MFM decoder --- MFM's fine, it's aligning to sync bytes
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which is hard.
2018-10-04 00:02:13 +02:00
David Given
fccabb3266
Add back in the hacky output file, for testing; replace the capture logic with
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an upcounter, and replace the pulse-in-high-bit stuff.
2018-10-03 19:45:27 +02:00
David Given
a8738915e9
You can now read complete disk images into a database file.
2018-10-03 00:03:50 +02:00
David Given
841c1ed516
Attempt to capture rollover events --- don't think it works. Add a basic
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command processor.
2018-10-02 23:03:07 +02:00
David Given
913829afbb
Discover timers; drastically simplify and betterify everything.
2018-10-02 00:17:37 +02:00
David Given
51cb1ae785
We just read our first floppy! Turns out the secret is to, once again, remove
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C7 from the board as it's preventing the READ DATA line showing anything.
2018-10-01 23:30:51 +02:00
David Given
4e19882d76
Archival checkin of messed-about non-working code to actually read data from
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disk. Something's wrong with the DMA; requesting a transfer every 2us with a TD
size of 64 bytes is somehow leading to an nrq interrupt every 8us. Mysterious.
2018-09-30 01:13:39 +02:00
David Given
e5155d98cc
You can now transfer gibberish from the FluxEngine to the PC to test bandwidth.
...
On Windows we're getting 620kB/s.
2018-09-29 18:32:06 +02:00
David Given
c174e5cafe
You can now measure the rotation speed from the interval between index pulses.
2018-09-29 16:37:04 +02:00
David Given
026842b8a4
There's a seek command now, which might even work.
2018-09-29 14:51:01 +02:00
David Given
7d98ec7e01
Okay, the USB stuff works! I can send a command to the device and receive the
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reply.
2018-09-29 12:13:00 +02:00
David Given
09ec9065cc
Fix incredibly stupid crashing bug.
2018-09-26 00:52:26 +02:00
David Given
d06e201933
Finally figure out the secrets of WCID, so we don't need a signed driver to do
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raw endpoints. Hurrah! Rip out the CDC stuff in favour of them.
2018-09-26 00:37:19 +02:00
David Given
7fc3b882d6
Lots of wasted time trying to make raw endpoints work --- but you can't do that
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on Windows because libusb can't talk to any device without a signed driver.
Stupid Windows.
Luckily I can get 500+kB/s out of CDC, even on Windows, so let's use that.
2018-09-25 00:11:06 +02:00
David Given
a332fd0308
Added some Unix stuff and a crude benchmark.
2018-09-24 01:12:14 +02:00
David Given
264cf47c00
Add the skeleton of the client-side program.
2018-09-23 13:13:29 +02:00
David Given
755ae2950d
Attempt to DMA data gibberish data from a fake acquisition unit and send it out
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over USB.
2018-09-23 02:05:20 +02:00
David Given
9d00a1e5ea
Bolt on USB UART.
2018-09-22 22:08:49 +02:00
David Given
a59c764dc5
Initial project boilerplate.
2018-09-22 21:44:33 +02:00
David Given
ee608cf66f
Initial commit
2018-09-22 21:05:57 +02:00
