Class: NXT::Interface::Usb

Inherits:
Base
  • Object
show all
Includes:
Exceptions
Defined in:
lib/nxt/interface/usb.rb

Overview

Implements USB connectivity to the NXT 2.0 module.

Constant Summary collapse

ID_VENDOR_LEGO = 
0x0694
ID_PRODUCT_NXT = 
0x0002
OUT_ENDPOINT = 
0x01
IN_ENDPOINT = 
0x82
TIMEOUT = 
10_000
READSIZE = 
64
INTERFACE = 
0

Instance Method Summary collapse

Instance Method Details

#connect ⇒ Object

Raises:



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# File 'lib/nxt/interface/usb.rb', line 19

def connect
  @usb_context = LIBUSB::Context.new
  @dev = @usb_context.devices(idVendor: ID_VENDOR_LEGO, idProduct: ID_PRODUCT_NXT).first

  raise UsbConnectionError, 'Could not find NXT attached as USB device' if @dev.nil?

  @connection = @dev.open
  @connection.claim_interface(INTERFACE)

  @connection
end

#connected? ⇒ Boolean

Returns:

  • (Boolean) 


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# File 'lib/nxt/interface/usb.rb', line 38

def connected?
  # FIXME: How do we check if the device is connected?
  @connection
end

#disconnect ⇒ Object 



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# File 'lib/nxt/interface/usb.rb', line 31

def disconnect
  return unless connected?

  @connection.release_interface(INTERFACE)
  @connection.close
end

#receive ⇒ Object 



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# File 'lib/nxt/interface/usb.rb', line 47

def receive
  @connection.bulk_transfer(endpoint: IN_ENDPOINT, dataIn: READSIZE, timeout: TIMEOUT).from_hex_str
end

#send(msg) ⇒ Object 



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# File 'lib/nxt/interface/usb.rb', line 43

def send(msg)
  @connection.bulk_transfer(endpoint: OUT_ENDPOINT, dataOut: msg.pack('C*'), timeout: TIMEOUT)
end