Hallo, a new test of the control unit plus the program-counter was very successful...it was possible to increase the clock speed:

This is the new clock timing (the old one was 10-10-20-10-10-10-10-10):

   Clock 0: Delete all registers which are set in Clock 1

   Clock 1: Set the registers

   Clock 2: Clear the control unit state register

   Clock 3: Set the control unit state register

And with this timing, a NOP command is finished in 156ms (compared to 180ms using the old timing), a "Load Accu with a constant" is finished in 312ms (before: 360ms). My tests are running a NOP followed by a LDA X command in an infinite loop, using this the program-counter was counting up until adress 512 in 79 seconds. Thats not bad for a relay system: the new timing only needs 87% of the time of the old one.

I hope in future i will be able to increase the speed again, only the ALU operations may need a longer timer period. We will see.