I have set up a Beaglebone Black with the latest Debian download. A
circuitco Bacon Cape is mounted.
I am attempting to read the 3-axis accelerometer data via i2c (p9_19,20)
using existing code downloaded from baconcapelabs (see code below):
var b = require('bonescript'); // Read BoneScript library
var port = '/dev/i2c-2';
var address = 0x1c;
b.i2cOpen(port, address, {}, onI2C); // Open I2C port
b.i2cWriteBytes(port, 0x2a, [0x00]); // Set STANDBY mode
b.i2cWriteBytes(port, 0x0e, [0x00]); // Set scale to 2G
b.i2cWriteBytes(port, 0x2a, [0x01]); // Set ACTIVE mode
setInterval(readA, 200); // Call readA() every 200ms
function onI2C() {
}
function readA() {
b.i2cReadBytes(port, 1, 6, onReadBytes);
}
function onReadBytes(x) {
if(x.event == 'callback') { var X = convertToG(x.res[0]); // First byte is
X
var Y = convertToG(x.res[2]); // Third byte is
Y
var Z = convertToG(x.res[4]); // Fifth byte is
Z
console.log('X: ' + X + ' Y: ' + Y + ' Z: ' + Z);
}
}
function convertToG(x) {
if(x >= 128) x = -((x^0xFF)+1); // Get two's complement
x = x / 64; // Scale to G
x = x.toFixed(2); // Limit decimal places
return(x);
}
*When I run this javascript code on Cloud9 IDE, I receive the following
error:*
/usr/local/lib/node_modules/bonescript/src/iic.js:15
if (m.ports[args.port[0]].path) path = m.ports[args.port[0]].path;
^
TypeError: Cannot read property 'path' of undefined
at Object.m.doOpen
(/usr/local/lib/node_modules/bonescript/src/iic.js:15:30)
at Object.newFunction [as i2cOpen]
(/usr/local/lib/node_modules/bonescript/src/my.js:451:31)
at Object.<anonymous> (/var/lib/cloud9/examples/BBB_Accelerometer.js:7:3)
at Module._compile (module.js:577:32)
at Object.Module._extensions..js (module.js:586:10)
at Module.load (module.js:494:32)
at tryModuleLoad (module.js:453:12)
at Function.Module._load (module.js:445:3)
at Timeout.Module.runMain [as _onTimeout] (module.js:611:10)
at ontimeout (timers.js:386:11)
at tryOnTimeout (timers.js:250:5)
at Timer.listOnTimeout (timers.js:214:5)
Changing the i2c channel to i2c-1 allows me to get past this error (had
seen that bonescript naming scheme different); however, “x.event” is now
undefined upon function onReadBytes.
SSH over USB using i2c tools indicates i2c2 acting as expected.
Any help would be much appreciated.
--
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