ni-fpga-rs

Use this Rust interface to interact with NI FPGAs! See NI's documentation about the FPGA C interface for more information.

Supported types

This interface supports reading and writing the following types, both indvidually and in fixed-sized arrays:

Primitive types

• bool
• u8
• u16
• u32
• u64
• i8
• i16
• i32
• i64
• f32 (for SGL registers)
• f64 (for DBL registers)

Clusters

Clusters are supported via a derive macro. Arrays of Clusters are not guaranteed to be supported.

#[derive(Cluster)]
struct PWMConfig {
    period: u16,
    min_high: u16,
}

Enums

Enums are supported via a derive macro. Arrays of Enums are also supported. One of u8, u16, u32, or u64 will be chosen as a backing type depending on the number of variants.

#[derive(Enum)]
enum SPIDebugState {
    Idle,
    CheckWindow,
    CheckAvailable,
    SetFIFOMark,
    EnableSPI,
    StuffFIFO,
    CheckMark,
    ShuffleData,
    Disable,
}

Fixed-point numeric types

Signed and unsigned FXP types are implemented in the fxp module. The types both take two generic parameters: word length and integer length. Word length is the actual number of bits used by the type. Integer length is such that the maximum value of the type is 2^{integer length} - 1 (half if it is signed) and the resolution of the type is 2^{integer length - word length}. For example, if an unsigned FXP has a word length of 8 and an integer length of 7, then its maximum value is 127 and its resolution is 0.5.

assert_eq!(
    SignedFXP::<8, 7>::from_float(-1.5)? + SignedFXP::<8, 7>::from_float(4.0)?,
    SignedFXP::<8, 7>::from_float(2.5)?,
);

Locating register offsets

Register offset can be found by introspecting /boot/user.lvbitx on a roboRIO. This file is also present in first-rust-competition/cross-images images.

Full example

use ni_fpga::Session;
use ni_fpga_macros::{Cluster, Enum};

#[derive(Cluster, Debug)]
struct PWMConfig {
    period: u16,
    min_high: u16,
}
#[derive(Cluster, Debug)]
struct AnalogTriggerOutput {
    in_hysteresis: bool,
    over_limit: bool,
    rising: bool,
    falling: bool,
}

#[derive(Enum, Debug)]
enum SPIDebugState {
    Idle,
    CheckWindow,
    CheckAvailable,
    SetFIFOMark,
    EnableSPI,
    StuffFIFO,
    CheckMark,
    ShuffleData,
    Disable,
}

fn main() -> Result<(), ni_fpga::Error> {
    let session = Session::open(
        "/boot/user.lvbitx",
        "264D0BA312FF00B741D4742415E1D470",
        "RIO0",
    )?;

    println!("Input voltage: {:?}", session.read::<u16>(99174)?);
    println!("{:#?}", session.read::<PWMConfig>(98536)?);
    println!("{:#?}", session.read::<[AnalogTriggerOutput; 8]>(98424)?);
    println!("{:#?}", session.read::<SPIDebugState>(99314)?);
    Ok(())
}

Contributing

Contributions are welcome and appreciated. Look at open issues to find tasks to work on. We especially need help with:

• Creating an automated testing strategy
• Improving documentation
• Adding support for IRQs and FIFOs (see NI API reference)