bp-spi.js

var SerialPort = require('serialport').SerialPort
var bl = require('bl')

module.exports = connect

function connect (device, cb) {
  var port = new SerialPort(device, { baudrate: 115200, highWaterMark: 1 })
  var timer = null
  var initialized = false
  var queue = []

  port.on('open', function () {
    reset()
    timer = setInterval(tryToEnterBinMode, 20)
    port.on('data', checkForBinMode)
  })

  function reset () {
    port.write([0x0d, 0x0d, 0x0d, 0x0d, 0x0d, 0x0d, 0x0d, 0x0d, 0x0d, 0x0d, 0x23])
  }

  function tryToEnterBinMode () {
    port.write([0x00])
  }

  function checkForBinMode (data) {
    if (data.toString() === 'BBIO1') {
      clearInterval(timer)
      port.removeListener('data', checkForBinMode)
      startSPI()
    }
  }

  function startSPI () {
    port.write([0x01]) // SPI mode
    port.write([0b01000000]) // disable power supplies
    port.write([0b10001010]) // 3.3v pin mode
    port.write([0b01100111]) // 8 MHz clock

    setTimeout(function () {
      port.write([0b01001000]) // wait 1 second then enable power to avoid spike
    }, 1000)

    initialized = true
    while (queue.length) {
      write(queue.shift())
    }
  }

  function write (data) {
    if (initialized) {
      var output = bl()
      output.append(data)
      for (var i = 0; i < output.length; i += 16) {
        var chunk = output.slice(i, i + 16)
        port.write([0b00010000 + chunk.length - 1])
        port.write(chunk)
      }
    } else {
      queue.push(data)
    }
  }
  return write
}