Ian Lesnet Brings I2C Sniffing to the Bus Pirate 5 — At Up to 500kHz
A missing and much-loved feature now arrives on the next-gen Bus Pirate 5, thanks to the Raspberry Pi RP2040's PIO blocks.
Ian Lesnet has announced that the Dangerous Prototypes Bus Pirate 5 debug tool is getting a new feature: an I2C sniffer, capable of capturing data at up to 500kHz — by offloading the work to the Raspberry Pi RP2040's Programmable Input/Output (PIO) blocks.
"Sniff I2C data up to 500kHz with the latest Bus Pirate firmware," Lesnet writes of the new feature, available to all Bus Pirate 5 owners through a free firmware upgrade. "The pico-i2c-sniffer project uses all four state machines of an RP2040 PIO to spy on I2C bus traffic. Useful for reverse engineering, debugging, and long duration event logging."
Launched last year, the Bus Pirate 5 is the latest in the long-running family of debugging and reverse-engineering gadgets — upgrading on earlier designs with a move to the dual-core Raspberry Pi RP2040 Arm Cortex-M0+ microcontroller, a color display, and a ring of RGB LEDs shining through a transparent case for good measure. The new microcontroller offers more than just the computational power for a light show, though: Programmable Input/Output (PIO) blocks, which can run state machines independently of the CPU cores.
It's these PIO blocks that power the new I2C sniffing capabilities on the Bus Pirate 5, which uses four state machines to pull data from an I2C bus at up to 500kHz. It's a feature that was present in the earlier Bus Pirate 3, but missing from its next-generation successor — until now.
More information is available in Lesnet's Bluesky post and on the Bus Pirate forum. "It really does work very well," Lesnet says of the feature, "great integration."