TOS patch for 1.44MB floppy support ?

[troed]

Epson 340 needed for the Atari way of detecting disk change to work :/

[exxos]

Epson 340 needed for the Atari way of detecting disk change to work :/

It seems to all work fine in GEM now. I haven't done massive testing, but its not corrupted anything swapping floppies back and forth several times without refreshing the A: drive window.

Not sure what the 340 does ? but on the H5 GAL it fiddles the WP IIRC to fool TOS into thinking there's been a floppy change. I understood that to be the "Media change fix".

[exxos]

Just had appear via ralcool I think...

ElcoHD_Compo.pdf

Doesn't give many hints, but seems they must have had their own OS at some point.

If you use this module in conjunction with EOS, the Enhanced Operating System for your Atari SII you dont need the included software as these routines are already build into EOS'

Once you have installed the module and the software has been run
from the AUT0 folder during start up, you will be able to read, write
and format high density disks as well as your old double density
disks. The driver expands some routines of the BIOS so that they
accept the new parameters necessary. The hardware ensures that the
speed of the FDC is doubled when needed. The software doubles the
step rate so that no timeout occurs. No further software or hardware
is necessary.
This method of using hardware and software offers continued
compatibility with software changes Atari may introduce for the new
Mega STb and TT computers now sold with high density drives.
Finely tuned logic in the software driver assures that the disk
recognize the type of disk inserted. This sane logic provides a highly
depenilable ernor recognition scheme'

[troed]

If you are using drive(s) without auto-sensing on pin 2 or if you jumper them to work this way, you have to connect all wires from the three way socket to grorrnd. use the ground connegtion next to the socket. Ttris is the recommended a',d best mode of operation, unless y_ou I9u use the high density drives with a pc Emulator. In this case B: m signalling used is the violet wire of the 10 way connector. This s'ire must be connected to pin 2 of the shugart nus ("o-put side).

If you want the disk drive to automatically detect density, you must
connect the appropriate wire from the three way connector to pin 2 oi
each of the high densrty drivds shugart Bus. At the seme time you
mtlst-not have any contact between pin 2 of the drive-s shugart Bus
and the motherboard.

Code: Select all

Yellow Pin 13 soundchip, YM2149F (I/O B0)
Blue Pin 12 sound chip, YM2149F (I/O B1)

So, unfortunately it seems that mod wasn't one to use the YM bit 6/7 either. They must've had their completely own way of detecting HD/DD patched into TOS - but I wonder if it didn't work the same way as Atari's. They don't seem to have had another way to figure out density otherwise.

[troed]

Not sure what the 340 does ? but on the H5 GAL it fiddles the WP IIRC to fool TOS into thinking there's been a floppy change. I understood that to be the "Media change fix".

Ah, you're right. Indeed the Epson 340 handles media change that way which is why Atari basically standardized on it (with some other drives used too). Faking the same behavior when using any other drive should work fine.