128MIKAY expansion for Pentagon 48

Layout by shock__,
Schematic by various authors (see schematic for full credits)
Version: 0.99 (tested on breadboard)

Contact: mos6502c@gmail.com or "Shockwav3" on the zx.pk.ru Forum
If you find any errors or want to suggest an improvement feel free to contact me.

License: CC-BY-SA-NC
Which means: 
- Don't remove the original credits.
- If you improve this layout/schematic you have to include the original files
- Non commercial. You're free to produce PCBs for yourself and others at a _fair_ price.

Short description: 
This interface allows you to add compatibility to Pentagon 128 programs on Pentagon 48 computers. For the memory
expansion exchange the DRAMs on board with 256K*1 DRAMs and follow the instructions in the .pdf. Modifications to
the mainboard of the computer are described in the .pdf
The value of C1 changes dependant on the type of logic IC used (74/74LS/74ALS/155/555/1533)
If you don't need the Kempston interface (it's redundant if the 8255 is used) you can leave out IC11, RN1, JP1.
MIKAY stands for "Mem - INT - Kempston - AY"

Enjoy!
shock__ - 03/02/2019