What Additional

Measurements

Must I Make?

Now it’s time to look at the hardware to see if it is causing incorrect data when the microprocessor reads this memory address. You decide you want to see what is happening on the address and data buses during this routine in the time domain.

In order to see the time domain, you need the timing analyzer.

Since the problem exists during the routine that starts at address 8930, you decide you want to see the timing waveforms on the address and data bus when the routine is running. You also want to see the control signals that control the read cycle. You will then compare the waveforms with the timing diagrams in the 68000 data book.

Your measurement, then, requires verification of:

correct timing of the control signals

stable addresses and data during the memory read

The control signals you must check are:

system clock

address strobe (AS)

lower and upper data strobes (LDS and UDS)

data transfer acknowledge (DTACK)

read/write (R/W)

HP 16510B

Using the Timing/State Analyzer

Front-Panel Reference

12-7