node-lpt

High-level bindings to parallel port for node.js.

Important: this module works only under linux through the parport driver, so you might need to compile kernel or modules (on gentoo mostly).

Installation

$ npm install lpt

Usage

var lpt = require('lpt')
  , port = new lpt.Port(0, 'byte', false) // open /dev/parport0 with forced `byte` mode set
  // , port = new lpt.Port(0) // the same

console.log(port.data) // read data register
console.log(port.status.busy) // get /BUSY pin status

port.data = 123 // write data register
port.control.init = true // write to control register

API

Constructor receives the following parameters:

• port number
• parallel port mode - optional. Can be:
  • spp
  • nibble
  • byte - default
  • epp
  • ecp
• negotiate port - optional. If true will try IEEE 1284 compliant mode negotiation.

Port class provides next fields:

| Field | Type | Description | Read/Write | Pin num | | --------------- | ---- | ------------- |:----------:| -------:| | data | byte | Data register | R/W | 2..9 | | control.init | bool | INIT | R/W | 16 | | control.select | bool | /SELECT_IN * | R/W | 17 | | control.autofd | bool | /AUTO_FEED * | R/W | 14 | | control.strobe | bool | /STROBE * | R/W | 1 | | status.ack | bool | ACK | R | 10 | | status.busy | bool | /BUSY * | R | 11 | | status.error | bool | ERROR | R | 15 | | status.select | bool | SELECT | R | 13 | | status.paperOut | bool | PAPEROUT | R | 12 | | - | - | Ground | - | 18..25 |

*Note that this pins are inverted by node-lpt itself

**You can read control pins only after you wrote something to it. Before that moment you can't rely on pin status

Useful links

• Standard Parallel Port
• Using in Linux
• Parallel port interfacing made easy
• ECP Description

License

MIT