I read that you were the one who got the digital speedo to read past the blinky 85 mph by having it go to kph then back to mph. My question is how did you do this. I would like to know how fast I am going at the end of the strip. I have a decent understanding of the electrical system, but can nto figure anything out on how to do this.
THANKS.

 

I designed a digital frequency detector, running at a 10 MHZ sample rate, which controls pulse dividing logic and the MPH to KPH switch over point. Its done in VHDL and implemented in an Actel FPGA. The FPGA is TTL level & interfaces to the 12 volt system through some voltage shifting circuitry. I haven't had time to install it in my '84 Berlinetta yet, but should be able to to so sometime in the near future.

Tim