var serial = { connectionId: -1, bitrate: 0, bytes_received: 0, bytes_sent: 0, transmitting: false, output_buffer: [], connect: function(path, options, callback) { var self = this; chrome.serial.connect(path, options, function(connectionInfo) { if (connectionInfo !== undefined) { self.connectionId = connectionInfo.connectionId; self.bitrate = connectionInfo.bitrate; self.bytes_received = 0; self.bytes_sent = 0; self.onReceive.addListener(function log_bytes_received(info) { self.bytes_received += info.data.byteLength; }); self.onReceiveError.addListener(function watch_for_on_receive_errors(info) { console.error(info); // valid conditions are 'disconnected', 'timeout', 'device_lost', 'system_error' if (info.error == 'system_error') { // we might be able to recover from this one chrome.serial.setPaused(self.connectionId, false, function() { console.log('SERIAL: Connection unpause after onReceiveError triggered'); }); } }); console.log('SERIAL: Connection opened with ID: ' + connectionInfo.connectionId + ', Baud: ' + connectionInfo.bitrate); callback(connectionInfo); } else { console.log('SERIAL: Failed to open serial port'); callback(false); } }); }, disconnect: function(callback) { var self = this; self.empty_output_buffer(); // remove listeners for (var i = (self.onReceive.listeners.length - 1); i >= 0; i--) { self.onReceive.removeListener(self.onReceive.listeners[i]); } for (var i = (self.onReceiveError.listeners.length - 1); i >= 0; i--) { self.onReceiveError.removeListener(self.onReceiveError.listeners[i]); } chrome.serial.disconnect(this.connectionId, function(result) { if (result) { console.log('SERIAL: Connection with ID: ' + self.connectionId + ' closed'); } else { console.log('SERIAL: Failed to close connection with ID: ' + self.connectionId + ' closed'); } console.log('SERIAL: Statistics - Sent: ' + self.bytes_sent + ' bytes, Received: ' + self.bytes_received + ' bytes'); self.connectionId = -1; self.bitrate = 0; callback(result); }); }, getDevices: function(callback) { chrome.serial.getDevices(function(devices_array) { var devices = []; devices_array.forEach(function(device) { devices.push(device.path); }); callback(devices); }); }, setControlSignals: function(signals, callback) { chrome.serial.setControlSignals(this.connectionId, signals, callback); }, getControlSignals: function(callback) { chrome.serial.getControlSignals(this.connectionId, callback); }, send: function(data, callback) { var self = this; self.output_buffer.push({'data': data, 'callback': callback}); if (!self.transmitting) { self.transmitting = true; function sending() { // store inside separate variables in case array gets destroyed var data = self.output_buffer[0].data; var callback = self.output_buffer[0].callback; chrome.serial.send(self.connectionId, data, function(sendInfo) { callback(sendInfo); self.output_buffer.shift(); self.bytes_sent += sendInfo.bytesSent; if (self.output_buffer.length) { // keep the buffer withing reasonable limits while (self.output_buffer.length > 500) { self.output_buffer.pop(); } sending(); } else { self.transmitting = false; } }); }; sending(); } }, onReceive: { listeners: [], addListener: function(function_reference) { var listener = chrome.serial.onReceive.addListener(function_reference); this.listeners.push(function_reference); }, removeListener: function(function_reference) { for (var i = (this.listeners.length - 1); i >= 0; i--) { if (this.listeners[i] == function_reference) { chrome.serial.onReceive.removeListener(function_reference); this.listeners.splice(i, 1); break; } } } }, onReceiveError: { listeners: [], addListener: function(function_reference) { var listener = chrome.serial.onReceiveError.addListener(function_reference); this.listeners.push(function_reference); }, removeListener: function(function_reference) { for (var i = (this.listeners.length - 1); i >= 0; i--) { if (this.listeners[i] == function_reference) { chrome.serial.onReceiveError.removeListener(function_reference); this.listeners.splice(i, 1); break; } } } }, empty_output_buffer: function() { this.output_buffer = []; this.transmitting = false; } };