RE: Serial Slave 0.7b out

From: Christopher Phillips (
Date: 2002-02-27 11:19:25

> For the next release I want to include a D64 reader and writer, and
> for that I need some fast code to read and write whole 1541 tracks at
> once. Anyone takers?

By remarkable coincidence, I just got my transfer tool working last night;
Host sends asm bootstrap to short basic bootstrap on c64+swiftlink, followed
by a small server that uploads a fast sector-read routine to 1541 before
transfering a .d64 back, one track at a time :)

I don't have the transfer working in the opposite direction yet, and the
code needs a lot of tidying up.  It could do with a bit of pipelining too;
at the moment the c64 tells the drive to read a sector, waits to get it
back, then sends a sector to the host.  I should really start the job for
the next sector read before starting the transfer to host.  Implementing a
sector increment other than '1' would also help.  Still, despite much work
to be done I'm currently getting a disk-side transferred in about five and a
half minutes, which is fast enough that I've finally started backing up my
40-odd disks of unfinished projects.  Yay!

The 1541 code transmits data back 2 bits at a time, one dibit every 8
cycles, and resyncs every byte (so probably closer to 80 than 40 cycles at
the moment).   I'm assembling using Andre Fachat's xa65 under Mac OS X.  The
assembler built 'out of the box', as does the Mac client (I just use posix
serial routines).  The drive stuff is in a single .a65 file, so I could send
you that 'as is', but I'd rather clean it up a bit first.

I haven't managed to get hardware handshaking working yet, so my code is
riddled with transmit-delays to get reliable operation.  I've requested it
at the host end, although the beta drivers for my USB-to-serial adapter
might be ignoring it, and I've no idea what I should be doing at the
swiftlink end, so it's probably broken at both ends!

Of course, if my sector-access stuff is useful to you and if serial slave
works on my Mac (OS X 10.1.3, keyspan usb to serial adaptor), I might just
drop my project altogether ;-).


Christopher Jam.

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