Partial tested midi interface.
Schematics based on https://groups.google.com/forum/#!topic/comp.sys.cbm/bPifzgUwfro
with 8k rom socket ($8000-9FFF).
To use rom, close JP1 and JP2
design partial tested
Rom found and running, midi detected by cynthcart v2.0
(note, running cynthcard V2.0 from 8k rom needs some crunching and relocation routine in rom as well)
Midi part not tested (I don't have midi...
Four Dot Matrix displays with Red/Green dots connected together. Data is sent for example from Commodore 64 (C64) and stored in shift registers which drive LEDs, meanwhile next line is loaded.
This design should be able to connect three boards together and fill at once with six data lines, and two clock lines. Therefore 8bit Commodore 64 is enough to handle it.
This is first version, REV 1.0, my f...
This project contains the non-simulation schematic, BoM and PCB design for the EasyEDA Uberclamp Overvoltage Protection Circuit.
The attached photo shows the circuit clamping at the designed clamp voltage of 6V, a 3V/ms 5V to 9.5V transient. The trace starts on the left with both input (yellow) and output (magenta) traces at 5V. The input and output then ramp up together at about 3V/ms until t...
68000 relocator for the Amiga 500(+)
with additional "Ranger" Memory .on the CPU bus (so not on the slow Chipmem bus).
expansion will disable internal trapdoor expansions that are not set to chipmem (A500 jumper on mainpcb)
output of U5 (memory decoder)
Y0 - $80000-$87FFFF
Y1 - $88000-$8FFFFF
Y2 - $90000-$97FFFF
Y3 - $98000-$9FFFFF
Y4 - $C0000-$C7FFFF
Y5 - $C8000-$CFFFFF
Y6 - $D0000-$D7FFFF
How to connect up two built and tested EasyEDA projects to build a complete replacement 5VDC and 9VAC power supply for the Commodore 64.
The design uses the EasyEDA Automotive 12V to USB 5V 2A output power adapter and Precision Commodore 64 Computer Saver PSU
overvoltage protection PCBs connected together with a 115V + 115V to 9V + 9V mains transformer, a pair of bridge
rectifiers, two 470...