🛠 Debugging an industrial communication bus with the SLogic32U3
Objectives
This tutorial aims to analyze the traffic of a high-speed serial communication bus (such as UART, SPI, or proprietary protocols) connecting a microcontroller to a peripheral in an automation system. With its 350 MHz bandwidth and 32 channels, the SLogic32U3 allows simultaneous capture of data, clock, and control lines (CS, IRQ) without packet loss, which is essential for debugging complex protocols.
Required Hardware
- Sipeed SLogic32U3 Logic Analyzer
- Mini-HDMI to probe adapter cables (or alligator clips)
- Target device (e.g., MCU board with SPI/UART bus)
- PC with SLogicView or sigrok-cli installed
- USB Power (via 10 Gbps Type-C port)
Steps
- Hardware Configuration: Connect the 4 mini-HDMI ports of the SLogic32U3 to your probes. Ensure a common ground between the analyzer and the target.
- Probe Connection: On the target, identify the bus lines (e.g., MOSI, MISO, SCLK, CS). Connect them to channels 0 to 3. Use the remaining channels for interrupt signals or relevant GPIOs.
- Software Setup: Open SLogicView. Select 4-channel mode to maximize the sampling rate to 1400 MS/s. Set the voltage threshold to 3.3 V (adjustable in 0.1 V steps) to match the target's logic levels.
- Data Capture: Start the acquisition. The 2 Gbit FIFO buffer allows for long captures. Trigger on the falling edge of the CS (Chip Select) line to isolate a complete transaction.
- Frame Analysis: Once captured, apply the protocol decoder (SPI/UART) in the software. Verify frame integrity and latency times between commands.