Michael of Acidbourbon built a clocked 8-bit random pattern generator and wrote a post on his blog detailing its assembly:
The idea behind this circuit is really simple:
- Build a white noise source
- Amplify the noise until it has CMOS/TTL logic level (0V=Lo, 5V=Hi)
- Use a clocked flip flop to sample the high frequency noise at a fixed rate (with a low frequency clock signal).
And then you should get a random sequence which changes at a fixed rate. If we use a shift register (a chain of flip flops), we can produce a multitude of binary random signals, which all toggle to the same rhythm.
Check out the video after the break.