Embassy NEORV32 HAL

HALs implement safe, idiomatic Rust APIs to use the hardware capabilities, so raw register manipulation is not needed.

The embassy-neorv32 HAL targets the open-source NEORV32 RISC-V microcontroller and implements both blocking and async APIs/drivers for most of the peripherals. Additionally, async and blocking traits from embedded-hal are implemented where appropriate.

Support

The HAL currently supports the following peripherals and features:

Peripherals

• SPI
• TWI
• GPIO
• UART
• DMA
• PWM
• TRNG
• WDT
• SYSINFO

Additional Features

• Dual-core support
• Embassy time-driver via CLINT mtimer

Additional peripheral support and features may be added if there is community interest!

Usage

Please see the examples folder for ideas on how to use this HAL in your own projects.
To run these examples, follow these steps:

• Install cargo-binutils
• Modify build target in examples/.cargo/config.toml to match your configuration
• Modify examples/memory.x to match the size of your configured DMEM and IMEM
• Modify examples/Cargo.toml features sim and fpga such that the tick-hz feature for embassy-time matches your configuration
• Modify UART_BAUD in examples/src/lib.rs to match your host UART
• Clone neorv32 v1.12.6
• Continue with one of the series of steps below depending on if running in simulation or on FPGA

Simulation

• Modify BASE in examples/run-sim to your neorv32 repo path
• Install GHDL simulator
• From examples folder, run cargo run-sim --release --bin hello-world
• For more help, see simulating the processor

FPGA over UART bootloader

• Modify BASE in examples/run-fpga to your neorv32 repo path
• Install picocom (or modify run-fpga to use your preferred tool)
• From the examples folder, run cargo run-fpga --release --bin hello-world
• Press reset button on FPGA
• If using picocom, manually follow these steps within host terminal:
• Type: Any key
• Type: u (Upload)
• Type: Ctrl+A Ctrl+S (send file)
• Type: hello-world-fpga
• For more help, see bootloader

Version

This HAL targets NEORV32 v1.12.6. There is no guarantee it will work for different versions.

References

• NEORV32 Datasheet
• NEORV32 User Guide