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right emulator, you don’t need the logic analyzer to trace program flow; you can
trace things like interrupt entry/exit (to provide timing information), document
lead/trail edge detection, and the memory locations that keep track of current
motor speed, document length, and the current interdocument spacing. Since you
couldn’t be sure that the firmware had good inputs, you might still use the logic
analyzer to track the actual document lengths (as measured by the sensor) so you
can compare the actual lengths to the lengths as measured by firmware.
Not all emulators, especially for smaller microcontrollers, have adequate trace
capability for this sort of problem. Many emulators cannot trace reads/writes to
specific addresses, although they might be able to breakpoint on such accesses.
Some modern debuggers provide additional tools that support system integra-
tion and debug. The p Vision2 debugger from Keil provides performance analysis
capabilities for 8051-based designs. This feature monitors how much time the soft-
ware spends in each routine, allowing you to measure the amount of timing margin
you have in your design.
Chapter 8 will look at multiprocessor systems.
202 Embedded Microprocessor System
