Experiment 12: Capturing Start/Stop Bits on Serial Communication

Objective: Capture and analyze the start and stop bits in UART (Universal Asynchronous Receiver-Transmitter) serial communication to understand how data is transmitted and received.

Steps:

1. Connect the Analyzer to TX and RX Lines:
   • Identify the TX (transmit) and RX (receive) lines of the UART communication system.
   • Connect the logic analyzer probes to the TX and RX lines. Ensure the voltage levels are compatible with the logic analyzer (e.g., 3.3V or 5V).
   • If necessary, connect the ground reference of the analyzer to the system's ground.
2. Set the Software to Detect Start/Stop Bits:
   • Configure the logic analyzer’s software to detect UART protocol signals. Set the baud rate, data bits, parity, and stop bits according to the system's configuration.
   • Ensure the software is set to capture the start bit, data bits, parity bit (if applicable), and stop bits for proper analysis.
   • Start the capture and observe the UART frames as they are transmitted.
3. Verify Timing and Data Frame Alignment:
   • Once data is captured, analyze the frames and ensure that the start bit (low) occurs first, followed by the data bits, optional parity bit, and stop bit (high).
   • Verify the timing between the bits. Ensure that each bit aligns with the expected duration based on the baud rate.
   • Check that the stop bit is correctly aligned to indicate the end of the data transmission and that there is no overlap or missing bits.
   • If necessary, adjust settings such as the sample rate or trigger conditions to capture the data more clearly.

Expected Outcome:

By completing this experiment, you will gain a deeper understanding of how start and stop bits frame serial data transmission. You'll be able to verify proper data transmission and troubleshoot issues in UART communication systems by analyzing the start and stop bits for any misalignments or errors.