[Coco] 256K SuperROMPak (32 Banks)

Zippster zippster278 at gmail.com
Sun Mar 22 08:28:02 EDT 2015


Sounds good, please consider a programming header or pads for the cpld chain if there
is space.

- Ed


> On Mar 22, 2015, at 1:08 AM, RETRO Innovations <go4retro at go4retro.com> wrote:
> 
> On 2/19/2015 5:13 AM, Mark McDougall wrote:
>> On 11/02/2015 3:53 PM, Chad H wrote:
>> 
>>> These are the posts I came across that made me realize it wasn't going to
>>> be so simple to tie into these lines.  We would need extra logic
>>> circuits/IC's....
>>> 
>>> http://comments.gmane.org/gmane.comp.hardware.tandy.coco/32296
>>> http://comments.gmane.org/gmane.comp.hardware.tandy.coco/32888
>> 
>> Yup, that'd be my mistake back then! ;)
>> 
>> Coincidentally, I'm planning on designing a flash cart in the near future, that will be programmable from the Coco in-circuit. It will also likely have a small serial EEPROM. There'll be a very limited run sold as a Lode Runner cartridge initially, but ultimately it'll be (re)programmable as a generic flash cartridge.
>> 
>> No ETA, treat it as vapourware.
>> 
>> Regards,
>> 
> Sorry to bring up an older subject, but I seem to have some spare copper on the MPI, and I thought I'd at least drop a CPLD and FLASH footprint on the board for later efforts to create a writeable flash cart
> 
> Reading the above forum posts, I gather that I need to:
> 
> * grab address lines 0-15 and q and e and r/w to decode the CTS line
>   by myself.
> * Create a register that turns off "write to cart space" functionality
>   unless the user specifically asks for it.
> 
> Thus, i think I need to bring the following into the CPLD:
> 
> * a0-a15 (16)
> * d0-a7 (8)
> * r/w (1)
> * e (1)
> * q (1)
> * reset (1)
> * flash_ce (1)
> * flash_oe (1)
> * flash_we (1)
> * scs (1) (not sure I need it, as it looks like I can just figure it
>   out from the other lines...)
> 
> Any others?
> 
> I know it's feature creep, but adding the footprints takes no time, and I wanted to get it in before I send the PCB off for proto etching (5 boards).  Any help would be appreciated.  I sent a note to Mark about it, but have not yet received a response.
> 
> Jim
> 



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