64Byte-ROM open source

1 Introduction

There is a composite structure in this open source circuit diagram, so some people may not understand it. The composite structure is a combination of diodes and short contacts, which are bound to facilitate subsequent PCB drawing.

The secondary storage scheme is the diode array storage scheme in digital circuits. Use solder to connect the diode to the circuit. The stored data is 0. Use a soldering iron to peel off the solder. The stored data is 1.

2. Device list

74HC138*9

1N4148WS-SOD-323 512 in total

Then there are 2.54mm pin headers 1*8P and 1*9P

When designing, we did not consider adding filter capacitors to each chip. This was not considered, but we have not encountered any problems in testing so far.

3. Test

Principle and PCB demonstration video

Finished product test video

4. Areas that can be improved and improved

The current solution is to use solder for operation, which requires a soldering iron. It may be changed to a short-circuit cap solution in the future. As for the DIP switch solution, it is not considered for the time being because the cost is high.

Later, pin headers and shorting caps will be used for programming design. The target capacity is 32Byte. Because there are a large number of diodes, SMT will be considered.