getting an error with this script

[ghost]

Im trying to test my spi with this loopback script

var rpio = require('rio');
var rxBuffer = rpio.spiTransfer(new Buffer('HELLOSPI'), 8);
for (var i = 0; i <= 7; i++) { 
 process.stdout.write(String.fromCharCode(rxBuffer[i]) + (i == 7 ? '\n' : ' '));
};

but i get this error.

/home/pi/Railway/node_modules/rpio/lib/rpio.js:641
    return binding.spi_transfer(txbuf, rxbuf, len);
                   ^

TypeError: Incorrect arguments
    at TypeError (native)
    at rpio.spiTransfer (/home/pi/Railway/node_modules/rpio/lib/rpio.js:641:17)
    at Object.<anonymous> (/home/pi/Railway/spitest.js:5:21)
    at Module._compile (module.js:434:26)
    at Object.Module._extensions..js (module.js:452:10)
    at Module.load (module.js:355:32)
    at Function.Module._load (module.js:310:12)
    at Function.Module.runMain (module.js:475:10)
    at startup (node.js:117:18)
    at node.js:951:3

[jperkin]

Hi! The API changed in recent versions so that the rxBuffer argument is now part of the function call. You would also need to allocate the buffer first, the binding won't do it for you and expects an existing Buffer to be provided.

So, something like:

var rxBuffer = new Buffer(8)
rpio.spiTransfer(new Buffer('HELLOSPI'), rxBuffer, 8)

Hope that helps, and sorry for the change, but it's part of making the API more orthogonal, and allows for a future version to return the number of bytes read if that proves to be useful.