🔗 I2C-Bridge: Multi-Processor Data Exchange

A high-reliability communication framework bridging the RP2040 (Master) and ATmega328P (Slave). This project implements a hardware-level dual-bus architecture designed to decouple high-bandwidth display data from time-critical sensor telemetry.

SCL Synchronization: By enforcing a strict Controller/Target relationship, this system eliminates the SCL clock-stretching collisions often found in multi-master configurations, ensuring 100% frame delivery across 3.3V/5V logic boundaries.

Get Firmware

MicroPython & C++ Source

Engineering Logic: Dual-Bus Isolation

The system utilizes the RP2040's dual hardware I2C controllers to optimize the Bit-Rate and prevent bus congestion:

I2C0 (GP16/GP17) - The Peripheral Bus: Negotiates with the Arduino Slave (Addr: 0x0A) using onRequest interrupt handlers for sub-millisecond data retrieval.
I2C1 - The Telemetry Bus: Dedicated local SSD1306 OLED interface. Isolating this bus ensures that slow display refresh rates (I2C overhead) do not block the polling of the MaxSonar transducer.
Cross-Logic Translation: Robust handshake protocols manage the 3.3V-to-5V signal transition, maintaining clear HIGH/LOW logic thresholds.

Technical Specifications

Subsystem	Engineering Specification
Master Microcontroller	Raspberry Pi Pico (Dual-Core ARM Cortex-M0+)
Slave Microcontroller	Arduino Nano (ATmega328P)
Communication Protocol	Synchronous Serial (I2C) @ 100/400 kHz
Interrupt Routine	ISR-based `Wire.onRequest()` (Arduino-side)
Addressing Scheme	7-bit (0x0A Slave / 0x3C Primary OLED)

Interrupt Safety & Buffer Management

To prevent Race Conditions, display updates are strictly prohibited within the Slave's interrupt context. This architecture centralizes the UI rendering on the Pico Master, ensuring the Arduino remains dedicated to high-precision sensor polling.

Asynchronous Telemetry Loop

The Arduino operates a local asynchronous polling loop for the MaxSonar sensor. It populates a data buffer that is served instantly upon a Master request, reducing the "Wait-State" of the main robot control loop.