[Coco] Bit 5 of DSKREG (was: Mocha & OS9)

[tim lindner]

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.

-- 
tim lindner
tlindner at ix.netcom.com                                            Bright