Verify signal operation

  • Use the Live Logic activity indicators to see if the signal is toggling
  • Use the Live Logic DVM to verify static logic levels and power supply voltages
  • Capture clock signals with Live Logic and use A/B marks to measure its period or frequency
  • Export start/end of execution marks on an unused pin captured by Live Logic. Use A/B marks to measure execution time

Capture I/O communication

  • Capture logic level RS-232 signals with Live Logic and verify the baud rate using A/B marks in frequency mode
  • Capture and decode logic level RS-232 signals using Live Logic or Logic Analyzer - see the ASCII messages
  • Capture and decode I2C transactions using Live Logic or Logic Analyzer
  • Capture PWM siganls using Live Logic and measure duty cyle

Handle difficult signals

  • Monitor and verify transient events with full sample rate resolution even when separated by long time intervals
  • Capture multiple transactions from a mostly sleeping processor
  • Generate a repeatable or controllable input simulation to test algorithms when an interface is missing or too unpredictable in the real world
  • Automate functional test scripts with data logging or .net remote control

Example use cases:

Capturing multiple “heartbeat” transactions

“One of the functions my microcontroller performed was to periodically send information to a control panel and receive control messages using a SPI interface. The SPI transaction occurred once each second. Sometimes the returning control message did not make sense given the information that was sent on the prior transaction. What I needed to to is capture both transactions. Watching with an oscilloscope I could get both transactions on the screen, but there wasn't enough time resolution to determine what the 8 bits were. Using the MB-500 Live Logic tool in single mode, I could capture both transitions and maintain 2ns resolution, allowing me to determine the content of the display information and debug my problem.”

Testing brown-out software

“In my battery-powered application, the microcontroller must not cause problems as the battery discharges. Brown-out interrupts allow my software to avoid sending corrupt data when the voltage level becomes too low for reliable operation. To test these software routines as the battery discharges is impractical — the discharge cycle for most batteries is too long. With the MB-500 Waveform Source, I can simulate the battery discharge cycle over minutes or seconds. This allows repeatable testing of the brown-out software routines.”

Catching PWM (Pulse-Width Modulation) problems in closed loop systems

“In my robotics application, I have an optical sensor that determines the direction of travel. The microcontroller converts the analog signal to a digital value, and a feedback routine adjusts the microcontroller's PWM output, changing the voltage driving the wheels and correcting for the error. Under some conditions, however, the PWM duration reaches 100%, and the loop is no longer closed. Using the MB-500 Logic Analyzer duration triggers, I can capture the microcontroller status outputs when the PWM approaches 100% and determine what was going on just before the loop opens up.”