[Coco] assembly programming on a 16K CoCo 2

Robert Gault robert.gault at worldnet.att.net
Tue Jun 27 18:46:07 EDT 2006


doctorx0079 wrote:
> Okay, so what are the pros and cons of ROM Paks versus floppies? What
> hardware do I need to get my PC to make ROM Paks and CoCo floppies? Making
> ROM Paks on the PC and running them on the CoCo 2 sounds good, since I'm not
> going to mass-produce them anyway.
  Based on your questions, I don't think you should consider trying to 
make ROM paks. 1) You need to be able to burn eproms. 2) You need to be 
able to construct the packs themselves.
  Both of the above require a high level of competency in computers and 
electronics.
  The advantage of a ROM pak is that it is essentially indestructible 
while disks can and do degrade with time becoming in some cases unusable.

> And with the floppy drive I just wanted
> to know if there was a way to get it to work with a 16K machine, using
> assembly language. Apparently you can't get at it through standard Color
> Basic but I thought you could maybe access it with assembly. Of course you
> wouldn't have a way to get the software going anyway, unless you could come
> up with a short program using POKE's that would load it from the floppy. Is
> there a way to do that?
  All of the Basic commands to access a floppy disk are contained in the 
ROM located in the disk controller. If you have a drive and controller 
installed on the Coco, then you also have some form of Disk Basic.
  It may not be necessary to have a 32K Coco to run Disk Basic. If it 
is,  add more memory to the Coco2. There should be some readers of this 
list that can sell the needed memory chips. You can also obtain an image 
of the Extended Basic ROM from the Internet and burn an eprom for the 
Coco2 if the Extended ROM is missing. However, you may have to ask if 
someone will do that for you.

  You could write your own ml code to process disk I/O. However, based 
again on your questions, it does not seem likely that you would be able 
to write that code.
  Before you should even think of that as a project, you should obtain a 
copy of the disassembled Disk Basic code and study it. If you can't 
understand what that code is doing, you won't be able to write your own.



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