[Coco] [Color Computer] Re: Coco flash cartridge

[Mark McDougall]

James Diffendaffer wrote:

> Is that the actual reset switch you planned on using or is that just
> what was available for rendering an image?
> Is that the best location for a switch?  Resetting the machine and
> page if it's bumped would be undesirable.  I'm not even sure it could
> go somewere else and fit in a standard game cart.

That's just what Altium Designer came up with for the button. I'm actually 
using one of these...
<http://au.farnell.com/jsp/Electrical/Switches+&+Accessories/OMRON+ELECTRONIC+COMPONENTS/B3F-1000/displayProduct.jsp?sku=176432>
It should be almost impossible to 'bump'. As it is, the PCB barely protrudes 
from the cartridge port, so it needs to be on the outer edge with the LED, 
otherwise there's no hope of access while it's plugged in.

> I'd like to develop some stuff for the board, let me know how much it
> will cost for one.  If you can provide the info on the ports ahead of
> time that would be nice.  

I'll let you know when we've paid for the panel and I work out how much I 
need to charge for the board to break even. All the parts are quite cheap 
except for the flash, and since I'm not buying in bulk it'll be the killer. 
You may want to purchase a bare board if you can do better on the flash?!? 
It's industry-standard TSOP40...

Decoding with A0 means there are 2 addresses within SCS# - ie. $FF40/1 and 
their aliases. I was planning on starting on the CPLD code sooner rather 
than later, but I can envisage:
@$0 - Bank Select (8-bits, WO)
@$1 - Control: WR - Bit0 = 16/32KB, Bit1 = auto-start enable (maybe?)
                RD - Bit0 = Flash RDY/BSY#
A jumper on the board sets default auto-start (Absent=auto-start) which I'm 
thinking can be overridden in s/w via the Control bit above?!? Haven't 
thought this through.
The RESET# switch on the Coco won't reset the bank select register. However, 
the reset button on the cart will, and perhaps will also reset the system?!?

How does that sound?

Regards,

-- 
|              Mark McDougall                | "Electrical Engineers do it
|  <http://members.iinet.net.au/~msmcdoug>   |   with less resistance!"