NEW CARD LAYOUT V2.3

UPDATE: New layout added to jlcpcb in December order

CAUTION! UNTESTED – WORK IN PROGRESS – UNDER CONSTRUCTION

- Testing completed-V2.2, issues U3 (74HCT04) Pins 1 & 2 swapped , Pins 5 & 6 swapped...
- Testing completed-V2.1. AFTER ISSUES REPAIRED, the card works GREAT using RomWBW code. See attachments for config info & PIC.
- Testing using SC126 z180 Board (https://smallcomputercentral.wordpress.com/sc126-z180-motherboard-rc2014/)
- See Attached for changes to ..\RomWBW\Source\HBIOS\Config\SCZ180_126.asm to add RC80-PROPIO support
- PRP (RC80-PROPIO) default IO Base address is set to A8h
- Edit ..\RomWBW\Source\HBIOS\prp.asm to change IO Base address (PRP_IOBASE .EQU $A8)

Objective: Migrate the PropIO 2.01 board to RC2014 environment utilizing a "bus compatible" RC80 bus.

The baseline "parent" design and the relevant Propeller Firmware can be found here: 
https://www.retrobrewcomputers.org/doku.php?id=boards:ecb:propio:start

And the baseline "parent" design derives software support from here: 
https://www.retrobrewcomputers.org/doku.php?id=software:firmwareos:romwbw:start

Many thanks to Wayne Warthen (PropIO 2.01) and the other original designers!

**Thank-You Jim (trawlergeek) for migrating this board from Wayne Warthen original "ECB" RetroBrew Design**


2020/07/11 - created first attempt at routing the board. 
- It is crowded 100mm x 75mm so far. 
- Standard RC2014 is about 100 x 49. We are not constrained to that profile. 
- Have replaced 74682 with 74688. 
- Added USR RC80 pin support for Z280 support using additional address card.

P4 
   High Address
1  Def - Jumper - 8Bit I/O
2  U5      For Use With
3  U6      16 / 24 / 32 Bit Address Decoder Card
4  U7      Still under development

   /WAIT
5  U1       For use with 
6  U2       40 pin to provide /WAIT
7  U3       on U1 or U2 or U3
   IEO-IEI Dasiy Chain
8 - Jumper to connect U4 & U8