[Coco] mess HD problem
Robert Gault
robert.gault at att.net
Wed Aug 6 19:09:49 EDT 2014
Bob Devries wrote:
> Hi all,
>
> well, changing the port address to $FF80 appears to have fixed the problem.
>
> I don't know how I came by a module with the incorrect hpa. Could it be that a
> previous version of emudsk used that address?
>
> Thanks for your input everyone.
>
> Regards, Bob Devries
> Dalby, QLD, Australia
>
Bob,
Here is some info.
*Technical specs on Virtual Hard Disk interface Alan DeKok: JVC, MESS and VCC
* Address Description
* ------- -----------
* FF80 Logical record number (high byte)
* FF81 Logical record number (middle byte)
* FF82 Logical record number (low byte)
* FF83 Command/status register
* FF84 Buffer address (high byte)
* FF85 Buffer address (low byte)
* FF86 DR# 0=first drive 1=second drive; MESS only
Look at MESS/SRC/machine/coco_vhd.c
-----------------------------------------------------------------------------
* The JV Coco3x has 2 .vhd drives with the second address set as:
* Address Description
* ------- -----------
* FFE0 Logical record number (high byte)
* FFE1 Logical record number (middle byte)
* FFE2 Logical record number (low byte)
* FFE3 Command/status register
* FFE4 Buffer address (high byte)
* FFE5 Buffer address (low byte)
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