Standalone hardware-integration scaffold for a Fluxkit + DRV8302 firmware project.

• embassy-stm32
• probe-rs runner via .cargo/config.toml
• defmt + RTT via defmt-rtt
• panic-probe
• Embassy-generated memory.x via embassy-stm32/memory-x
• standalone flake.nix for an embedded-capable Rust dev shell
• path dependencies back to the local Fluxkit workspace

Open the example shell directly from this crate:

cd ~/Develop/fluxkit_drv8302_example
XDG_CACHE_HOME=/tmp/fluxkit-nix-cache nix develop

This crate now contains a concrete board-level fluxkit-hal implementation for the current NUCLEO-G431KB + AS5048A + DRV8302 wiring.

• TIM1-based 3-PWM output for DRV8302 on PA8/PA9/PA10
• ADC1 injected current sampling on PA0/PA1, triggered from TIM1 CC4
• AS5048A SPI sensor on PB3/PB4/PB5 with dedicated PB0 chip select
• AS5048A sampling requested by separate TIM6 update interrupts at 10 kHz
• SPI1 encoder transfers run through a raw DMA IRQ state machine instead of blocking inside the timer ISR
• direct-drive output sensing implemented by sharing the AS5048A path for both rotor and output
• fixed placeholder sensors for bus voltage and winding temperature until real hardware is wired
• startup current zeroing with bounded sample collection and span checks before higher-level control

Current hardware target:

• ST NUCLEO-G431KB
• AS5048A absolute encoder over SPI at 3.3 V
• DRV8302 breakout in 3-PWM mode
• Cubemars GL60 KV55
• encoder-based PMSM/BLDC FOC

Control split:

• MCU generates 3 independent PWM phase commands
• DRV8302 handles gate drive and current-shunt amplification
• AS5048A provides rotor angle over SPI
• output sensing is currently assumed to be the same direct-drive axis as the rotor encoder

Important notes:

• D0 and D1 are repurposed as PWM outputs, not UART
• EN_GATE should stay low through early bring-up
• nFAULT and nOCTW are active-low inputs
• AS5048A chip select is a dedicated GPIO on PB0

• M_PWM tied high: 3-PWM mode
• GAIN tied high: 40 V/V
• M_OC tied high: latched shutdown OCP mode
• OC_ADJ must be driven by an external threshold divider, not left floating

Assumed current-sense configuration:

• dual shunt outputs: SO-1, SO-2
• shunt resistance: 0.002 ohm
• shunt amplifier gain: 40 V/V
• ADC reference: 3.3 V
• zero-current midpoint: 1.65 V

Conversion model:

• Vout = 1.65 V + 0.08 * Iphase
• Iphase = (Vout - 1.65) / 0.08

Implementation note:

• ADC samples should be treated as signed current signals around the midpoint
• this example now performs zero-current offset calibration at startup before higher-level control is enabled

• NUCLEO 3V3 powers AS5048A and DRV8302 logic/mode pins
• external PSU powers the DRV8302 motor bus
• MCU ground, encoder ground, DRV logic ground, and motor PSU negative must share a common ground
• do not power the motor stage from NUCLEO 3V3 or 5V

Recommended bring-up order:

1. keep EN_GATE low
2. initialize clocks, GPIO, ADC, timers, and SPI
3. verify AS5048A communication
4. enable PWM in neutral and assert EN_GATE
5. calibrate SO-1 / SO-2 zero-current offsets
6. verify encoder/current/fault heartbeat while PWM remains neutral
7. enable higher-level control or calibration once hardware checks are clean
8. continuously monitor nFAULT and optionally nOCTW

• MCU family: STM32G4
• MCU: STM32G431KB
• default chip runner: STM32G431KBTx
• default target: thumbv7em-none-eabihf
• linker memory layout comes from Embassy's generated memory.x

• src/board.rs
• src/inverter.rs
• src/sensors.rs
• src/runtime.rs
• src/main.rs

src/main.rs now exercises the board-level HAL implementation:

• brings up TIM1 center-aligned 3-PWM
• configures ADC1 injected conversions from TIM1 CC4
• brings up the AS5048A SPI encoder path at 5 MHz
• uses TIM6_DAC as a 10 kHz encoder sample launch source
• advances AS5048A reads from DMA1_CHANNEL1 / DMA1_CHANNEL2 IRQs
• enables neutral PWM and asserts DRV8302 EN_GATE
• runs a bounded idle SO-1 / SO-2 zeroing routine with fresh-sample and span checks
• keeps PWM neutral while logging board diagnostics at 1 Hz
• leaves Fluxkit motor calibration disabled until hardware validation is complete
• the dormant motor-calibration path is already updated for the new Fluxkit API and uses a PLL rotor estimator when re-enabled

Current software assumptions:

• rotor and output sensors are the same physical AS5048A signal path
• bus voltage is currently a fixed 20 V placeholder value
• winding temperature is currently a fixed placeholder value

Note:

• PB3 / D13 is also the NUCLEO user LED pin when SB15 connects the LED path
• during encoder reads, that pin is used as SPI clock, not as a user LED