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    spi-node
    TypeScript icon, indicating that this package has built-in type declarations

    3.0.1 • Public • Published

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    spi-node

    Communicate with devices using SPI directly from your Node.js app. Data transfers are executed asynchronously in their own thread. Supports mock data transfers on machines without SPI support for easy local development. Uses Node's now-stable N-API for native addon support. Written in Typescript.

    Installation

    To install:

    npm install --save spi-node
    

    When installing, the native binaries will be rebuilt and added to your project's /build directory. If installing on a machine without SPI support, you'll see this warning from the compiler:

    warning: "SPI not supported on this machine" [-W#warnings]
    

    Not a problem, you can programatically opt-in to using mock data transfers by overriding the underlying transfer function.

    Usage

    [TODO: Add MCP3008 example]

    API

    The spi-node package exports the following:

    import {
      Flags,
      Mode,
      Order,
      SPI,
      Settings,         // TS type
      SpiAddon          // TS type
      TransferCallback, // TS type
      TransferConfig,   // TS type
      TransferFunction, // TS type
    } from 'spi-node';
    

    Flags Enum

    Flags is an enum of the underlying flags used to set an SPI channel's mode. You (probably) won't need to use Flags directly as they're built into the values of Mode.

    enum Flags {
      CPHA = 0x01,
      CPOL = 0x02
    }
    
    • Flags.CPOL: If set, sets clock polarity such that the leading edge of the clock cycle is a falling edge.
    • Flags.CPHA: If set, data is read on the leading edge of the clock cycle.

    Mode Enum

    Mode is an enum of the four possible SPI modes, which are just permutations of the Flags.

    enum Mode {
      M0 =	0 | 0,
      M1 =	0 | Flags.CPHA,
      M2 =	Flags.CPOL | 0,
      M3 =	Flags.CPOL | Flags.CPHA,
    }
    

    The default mode of an SPI instance is Mode.M0.

    Order Enum

    Order is an enum whose values set the bit order of data transferred over an SPI connection.

    enum Order {
      MSB_FIRST = 0,
      LSB_FIRST = 1,
    }
    

    The default order of an SPI instance is Order.MSB_FIRST.

    SPI Class

    [TODO: Add descriptions]

    Static properties & constructors

    Property SPI.spiSupported: boolean

    ...

    Constructor SPI.fromDevicePath(path: string)

    ...

    Constructor SPI.fromFileDescriptor(fd: number)

    ...


    Properties

    mode: Mode

    ...

    order: Order

    ...

    speed: number

    ...

    transferOverride: TransferFunction | null

    ...


    Methods

    write(dataIn: Buffer): Promise<Buffer>

    ...

    read(readcount: number): Promise<Buffer>

    ...

    transfer(dataIn: Buffer, readcount: number): Promise<Buffer>

    ...

    close(): void

    ...


    Chainable setter methods

    All of the properties of an SPI instance can be set using chainable setter methods, allowing you to instantiate and configure an SPI connection in one go:

    const spi = SPI.fromDevicePath('/dev/spidev0.0')
      .setMode(Mode.M0)
      .setOrder(Order.MSB_FIRST)
      .setSpeed(1e7)
      .setTransferOverride(dataIn => Promise.resolve(dataIn)); // jumper MISO/MOSI
    

    Install

    npm i spi-node

    DownloadsWeekly Downloads

    14

    Version

    3.0.1

    License

    MITNFA

    Unpacked Size

    24.8 kB

    Total Files

    24

    Last publish

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