One of the central engineering challenges in my custom automotive digital dash project is controlling hundreds of SK6805-EC10 addressable RGB LEDs spread across multiple gauge clusters. Each gauge contains dozens of LEDs arranged into segments—groups of LEDs that must illuminate in perfect unison to replicate the clean, high-contrast look of the Toyota Supra's third-generation factory VFD dashboard.
To deliver smooth, synchronized lighting at ~30FPS across the entire dash, I designed a distributed architecture using one microcontroller per gauge. The MCU receives high-level data (via I²C) from a central ESP32-S3 controller and then generates precise, high-bandwidth timing signals to its local LED segments.
After evaluating several microcontroller families, I selected the STM32G031F6P6 for each gauge board. This page explains how the G031 is used technically, and why it became the best choice for the job.
Each gauge includes:
To drive these LEDs reliably, the STM32G031 performs several key functions.
SK6805 LEDs require strict timing:
Distributing this workload to individual MCUs keeps timing local, stable, and immune to long cable runs or bus latency.
On each gauge, the G031 uses:
This approach offloads nearly all LED timing from the CPU. Once a DMA transfer begins, the LED data stream is produced autonomously by hardware. The CPU is free to:
This architecture is extremely predictable, low-jitter, and scales well as segment sizes grow.
The central ESP32-S3 converts CANBus and vehicle sensor signals into gauge values, then broadcasts them over a resilient I²C bus to each gauge.
Each G031:
Because the G031 only receives logical data (not raw LED frames), the I²C bus carries only a few dozen bytes per gauge per frame — not Mbps-scale data.
This massively reduces wiring complexity and keeps gauge-to-gauge timing consistent.
Unlike many small MCUs, the G031 supports stable timing from an external clock source. For this project, each gauge PCB includes a high-accuracy MEMS oscillator to ensure:
Automotive temperature swings can easily push internal RC oscillators out of spec; using a MEMS oscillator eliminates this risk entirely.
One gauge includes a 150 mm span with ~60 LEDs wired in parallel — a significant capacitive load.
The G031 handles this safely because:
Signal degradation is mitigated through PCB layout, local buffering, and tight control of rise/fall times.
There are many microcontrollers that can drive addressable LEDs — so why use the G031 specifically?
After extensive testing, cost analysis, and architecture simulation, it became clear that the G031 hit the perfect balance of price, features, and robustness.
The G031 includes:
Crucially, it does not include expensive features I don't need:
This keeps cost and power consumption extremely low.
Competing options were either:
The G031 hits the "Goldilocks" zone:
I did consider using a single large processor (e.g., STM32H7 or ESP32) to drive all gauge LEDs directly. This was rejected because:
Distributed control is a key part of meeting automotive reliability expectations.
Before selecting the G031, I prototyped:
The G031 consistently delivered stable LED timing even in stressful conditions:
This gave me the confidence that the G031 would continue performing under real-world automotive conditions.
The STM32G031F6P6 turned out to be the ideal microcontroller for this digital dash:
This decision wasn't just about raw specs — it was about choosing the microcontroller that best fit the system architecture, the mechanical constraints of the gauges, and the reliability requirements of an automotive environment.
By leveraging the G031's strengths, every gauge in the dash can render smooth, vivid, synchronized lighting that brings a modern feel to a classic platform.