/*
* Read a single pair of (X,Y) values from the ADXL202EVB board.
* TODO: Better return value, or declare as throwing exception for errs
*/
public static double[] chipRead() {
double[] retval = {0.0, 0.0};
byte[] rawBuf = {0, 0, 0, 0};
int[] vals = {0, 0};
try {
// Read is triggered by sending 'G' to board
outputStream.write('G');
// Wait for all 4 result bytes to arrive
// TODO: Finite wait w/error return if data never arrives
while (inputStream.available() < 4) {
Thread.sleep(1);
}
inputStream.read(rawBuf, 0, 4);
// Convert from raw bytes to 16-bit signed integers, carefully
Byte bTmp = new Byte(rawBuf[0]);
vals[0] = bTmp.intValue() * 256;
bTmp = new Byte(rawBuf[1]);
vals[0] += bTmp.intValue();
bTmp = new Byte(rawBuf[2]);
vals[1] = bTmp.intValue() * 256;
bTmp = new Byte(rawBuf[3]);
vals[1] += bTmp.intValue();
// See ADXL202EVB specs for details on conversion
retval[0] = (((vals[0] / 100.0) - 50.0) / 12.5);
retval[1] = (((vals[1] / 100.0) - 50.0) / 12.5);
System.out.println("X: " + retval[0] + " Y: " + retval[1]);
} catch (Exception ioe) {
System.out.println("Error on data transmission");
}
return (retval);
}
/**
* Convert a byte array to a hex string
*
* @param bytes byte array to convert to a hex string
* @return return a String in hex representing the byte array
*/
public String toHexString(byte[] bytes) {
StringBuffer result = new StringBuffer("0x");
for (int i = 0; i < bytes.length; i++) {
Byte aByte = new Byte(bytes[i]);
Integer anInt = new Integer(aByte.intValue());
String hexVal = Integer.toHexString(anInt.intValue());
if (hexVal.length() > SIZE) hexVal = hexVal.substring(hexVal.length() - SIZE);
result.append(
(SIZE > hexVal.length() ? ZEROS.substring(0, SIZE - hexVal.length()) : "") + hexVal);
}
return (result.toString());
}
