This is a100x100mm 1802 board that has a USB loader as well as a header that could be connected to toggle switches for slower loading.

A single 128k RAM chip is mapped with up to 4 16k sized windows from anywhere in the 128k space. Obviously remapping a block where it is executing from could get interesting.

The 8 bit upper address latch is under the RAM chip, so RAM should be in a socket to give clearance.

A DP4T rotary switch selects between LOAD, RESET, RUN, and WAIT

Status LEDs show the switch selected operating mode, as well as CPU state FETCH, EXECUTE, DMA, or INTERRUPT

CPU clock can come from crystal, backplane connector, or from USB FIFO chip (fast!)

The backplane is 32 pins wide so will fit onto a Vero board for expansion

This is an extremely early untested release so may have some bugs, faults and plain bad assumptions.

I have selected a restrictive license but would open up for any co-operative effort.

Use of this PCB is entirely at you own risk!

Have not received PCBs yet to test, although definitely will be a version 2 soon to fix/enhance

preliminary BOM uploaded but values have not yet been tested.

Construction and schematic highlights in pdf file