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Hi Charlie, Congratulations on another fine replacement part! It's not particularly easy for FlashFloppy to do what you describe as the drive-select ISR has tight timing requirements. It is specialised to only assert lines on select, and deassert them on deselect. We could plausibly add a special secondary handler, as I do for Amiga_HD_ID() which toggles pin 34 on each deselect-select cycle. This could take responsibility for pin 2 at the expense of ISR latency. For mixed multi-drive setups, it would be fairly easy to solder in a low-drop diode between the real drive's select line, and line 2, on the drive or even in the cable? Regards, |
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Hi Keir,
I have just finished the design of a WD1772 floppy controller replacement which runs at either 8MHz and 16MHz (automatically switched by setting a config pin to either 0V or +5V) for both DD/SD and HD modes. I would like to use pin 2 of the gotek to control the density mode but the way it is programmed means that at idle (disk select not asserted) the output is always +5V whether pin2 = dens or pin = ndens is set in FF.CFG. I'm guessing that this is due to the output being open collector?
Observed behaviour is as follows:
With pin2 = dens, idle gives +5V. When the disk is selected DD = +5V, HD = 0V
With pin2 = ndens, idle gives +5V, When the disk is selected then DD = 0V, HD = +5V.
Could an additional setting be created for pin2 so that idle gives 0V and when the disk is selected then DD = 0V, HD = +5V?
For the auto switching of the WD1772 clone this means for drives without density signalling the default could be either DD/SD or HD depending on how the idle (gotek not selected) setting was configured. For drives that do have density signalling on pin 2 (due to modification) then the current settings work fine.
If you need further info please let me know.
Regards,
Charlie
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