Stabilizer Firmware

Hardware

Applications

This firmware offers a library of hardware and software functionality targeting the use of the Stabilizer hardware in various digital signal processing applications commonly occurring in Quantum Technology. It provides abstractions over the fast analog inputs and outputs, time stamping, Pounder DDS interfaces and a collection of tailored and optimized digital signal processing algorithms (IIR, FIR, Lockin, PLL, reciprocal PLL, Unwrapper, Lowpass, Cosine-Sine, Atan2). An application can compose and configure these hardware and software components to implement different use cases. Several applications are provides by default:

Dual-IIR

• dual channel
• SPI ADC
• SPI DAC
• up to 800 kHz rate, timed sampling
• down to 2 µs latency
• f32 IIR math
• generic biquad (second order) IIR filter
• anti-windup
• derivative kick avoidance

Lockin

• Up to 800 kHz sampling
• Up to 400 kHz modulation frequency
• Reciprocal PLL for external reference
• Internal reference
• Adjustable PLL and locking time constants
• Adjustable phase offset and harmonic index
• Different output modes (in-phase, quadrature, magnitude, log2 power, phase, frequency)

Minimal bootstrapping documentation

• Clone or download this
• Get rustup
• Minimum supported Rust version (MSRV) is 1.52.0
• Install target support: rustup target add thumbv7em-none-eabihf
• Install probe-run: cargo install probe-run
• cargo run --release --bin dual-iir
• When using debug (non --release) mode, increase the sample interval significantly. The added error checking code and missing optimizations may lead to the code missing deadlines and panicing.

Alternative flashing tools

Cargo-embed

• Install cargo-embed: cargo install cargo-embed
• Program the device: cargo embed --bin dual-iir --release

GDB/OpenOCD

• Get a recent openocd, a JTAG adapter ("st-link" or some clone) and everything connected and permissions setup. Most Nucleo boards have a detachable ST-Link v2 and are cheap.[^swd]
• Get a multiarch gdb (or a cross arm gdb and edit .cargo/config accordingly)
• openocd -f stabilizer.cfg and leave it running
• cargo run --release

USB-DFU

• Get cargo-binutils
• cargo objcopy --release --bin dual-iir -- -O binary dual-iir.bin or arm-none-eabi-objcopy -O binary target/thumbv7em-none-eabihf/release/dual-iir dual-iir.bin
• Install the DFU USB tool (dfu-util)
• Connect to the Micro USB connector below the RJ45
• Short JC2/BOOT
• dfu-util -a 0 -s 0x08000000:leave -D dual-iir.bin

ST-Link virtual mass storage

• Prepare dual-iir.bin like above
• Connect the ST-Link debugger
• Copy dual-iir.bin to the NODE_H743ZI virtual mass storage device

Protocol

Stabilizer can be configured via MQTT. Refer to miniconf for more information about topics. A basic command line interface is available in miniconf.py. Telemetry is published via MQTT as well.