[Coco] Bit 5 of DSKREG (was: Mocha & OS9)
tlindner at ix.netcom.com
Wed Jan 28 11:56:56 EST 2004
Brad Grier <bradgrier at cox.net> wrote:
> I downloaded the MESS source (I should have done this earlier). There's
> a comment in cococart.c that bit 5 of the control register at $ff40 not
> only controls floppy density but is an "NMI enable flag".
I wrote that.
I discovered it from my reading of the various schematics for various
floppy disk controllers.
I could be wrong, I am not an expert reading schematics.
Maybe Mark Marlette could chime in to settle this question.
Since this bit is doeumented to enable/disable the single density mode,
I thought I might ask a question regarding that:
Does anyone have a single density I/O kernal? I am in the process of
adding single density support to the CoCo driver in MESS and would like
some _real_world_ code to test.
I have been thinking of tracking down a copy of Flex.
tlindner at ix.netcom.com Bright
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