[Coco] Re: 512K EEPROM...or 4MB!!?

[Zippster]

The use of a CPLD with 5v tolerant inputs is something people interfacing
5v logic to modern, lower voltage parts should take note of if they weren’t
already aware of it.  Especially if there is also a need for some logic (address
decoding, etc.) that can be handled at the same time.

I may use a similar tactic on the FPGA Experimenter’s Board, though for
shifting (with directional controls) only, as all decoding, etc., will be handled in 
the FPGA.  With the purpose being reducing the number of ICs and simplifying
assembly.

Sounds like an ideal way to handle the interface on your 8MB board Jim.
Very nice.  :)

- Ed


> On Dec 9, 2015, at 1:42 PM, RETRO Innovations <go4retro at go4retro.com> wrote:
> 
>   I am currently using an 29lv640eb, which is a 3V3 part.  I then use a
>   single xc95144xl to do voltage shift, implement the bank registers and
>   a config register (reading the switches, allowing writes to go to the
>   ROM, turning on the LED, and moving the base address of the 4
>   registers) and implementing the "full adder" that takes the bank
>   register to the incoming address lines A15:11.
> 
>   I have found a cheaper 8MB ROM I am checking out, but I don't remember
>   the part number.  Search on Digikey and you'll find it.
> 
>   Jim
>