/*JSON{
"type" : "method",
"class" : "I2C",
"name" : "readFrom",
"generate" : "jswrap_i2c_readFrom",
"params" : [
["address","JsVar","The 7 bit address of the device to request bytes from, or an object of the form `{address:12, stop:false}` to send this data without a STOP signal."],
["quantity","int32","The number of bytes to request"]
],
"return" : ["JsVar","The data that was returned - as a Uint8Array"],
"return_object" : "Uint8Array"
}
Request bytes from the given slave device, and return them as a Uint8Array (packed array of bytes). This is like using Arduino Wire's requestFrom, available and read functions. Sends a STOP
*/
JsVar *jswrap_i2c_readFrom(JsVar *parent, JsVar *addressVar, int nBytes) {
IOEventFlags device = jsiGetDeviceFromClass(parent);
if (!DEVICE_IS_I2C(device)) return 0;
bool sendStop = true;
int address = i2c_get_address(addressVar, &sendStop);
if (nBytes<=0)
return 0;
if ((unsigned int)nBytes+256 > jsuGetFreeStack()) {
jsExceptionHere(JSET_ERROR, "Not enough free stack to receive this amount of data");
return 0;
}
unsigned char *buf = (unsigned char *)alloca((size_t)nBytes);
jshI2CRead(device, (unsigned char)address, nBytes, buf, sendStop);
JsVar *array = jsvNewTypedArray(ARRAYBUFFERVIEW_UINT8, nBytes);
if (array) {
JsvArrayBufferIterator it;
jsvArrayBufferIteratorNew(&it, array, 0);
unsigned int i;
for (i=0;i<(unsigned)nBytes;i++) {
jsvArrayBufferIteratorSetByteValue(&it, (char)buf[i]);
jsvArrayBufferIteratorNext(&it);
}
jsvArrayBufferIteratorFree(&it);
}
return array;
}
void jswrap_i2c_writeTo(JsVar *parent, JsVar *addressVar, JsVar *args) {
IOEventFlags device = jsiGetDeviceFromClass(parent);
if (!DEVICE_IS_I2C(device)) return;
bool sendStop = true;
int address = i2c_get_address(addressVar, &sendStop);
size_t l = (size_t)jsvIterateCallbackCount(args);
if (l+256 > jsuGetFreeStack()) {
jsExceptionHere(JSET_ERROR, "Not enough free stack to send this amount of data");
return;
}
unsigned char *data = (unsigned char *)alloca(l);
jsvIterateCallbackToBytes(args, data, l);
jshI2CWrite(device, (unsigned char)address, l, data, sendStop);
}
/*JSON{
"type" : "staticmethod",
"ifndef" : "SAVE_ON_FLASH",
"class" : "E",
"name" : "FFT",
"generate" : "jswrap_espruino_FFT",
"params" : [
["arrReal","JsVar","An array of real values"],
["arrImage","JsVar","An array of imaginary values (or if undefined, all values will be taken to be 0)"],
["inverse","bool","Set this to true if you want an inverse FFT - otherwise leave as 0"]
]
}
Performs a Fast Fourier Transform (fft) on the supplied data and writes it back into the original arrays. Note that if only one array is supplied, the data written back is the modulus of the complex result `sqrt(r*r+i*i)`.
*/
void jswrap_espruino_FFT(JsVar *arrReal, JsVar *arrImag, bool inverse) {
if (!(jsvIsIterable(arrReal)) ||
!(jsvIsUndefined(arrImag) || jsvIsIterable(arrImag))) {
jsExceptionHere(JSET_ERROR, "Expecting first 2 arguments to be iterable or undefined, not %t and %t", arrReal, arrImag);
return;
}
// get length and work out power of 2
size_t l = (size_t)jsvGetLength(arrReal);
size_t pow2 = 1;
int order = 0;
while (pow2 < l) {
pow2 <<= 1;
order++;
}
if (jsuGetFreeStack() < 100+sizeof(double)*pow2*2) {
jsExceptionHere(JSET_ERROR, "Insufficient stack for computing FFT");
return;
}
double *vReal = (double*)alloca(sizeof(double)*pow2);
double *vImag = (double*)alloca(sizeof(double)*pow2);
unsigned int i;
for (i=0;i<pow2;i++) {
vReal[i]=0;
vImag[i]=0;
}
// load data
JsvIterator it;
jsvIteratorNew(&it, arrReal);
i=0;
while (jsvIteratorHasElement(&it)) {
vReal[i++] = jsvIteratorGetFloatValue(&it);
jsvIteratorNext(&it);
}
jsvIteratorFree(&it);
if (jsvIsIterable(arrImag)) {
jsvIteratorNew(&it, arrImag);
i=0;
while (i<pow2 && jsvIteratorHasElement(&it)) {
vImag[i++] = jsvIteratorGetFloatValue(&it);
jsvIteratorNext(&it);
}
jsvIteratorFree(&it);
}
// do FFT
FFT(inverse ? -1 : 1, order, vReal, vImag);
// Put the results back
bool useModulus = jsvIsIterable(arrImag);
jsvIteratorNew(&it, arrReal);
i=0;
while (jsvIteratorHasElement(&it)) {
JsVarFloat f;
if (useModulus)
f = jswrap_math_sqrt(vReal[i]*vReal[i] + vImag[i]*vImag[i]);
else
f = vReal[i];
jsvUnLock(jsvIteratorSetValue(&it, jsvNewFromFloat(f)));
i++;
jsvIteratorNext(&it);
}
jsvIteratorFree(&it);
if (jsvIsIterable(arrImag)) {
jsvIteratorNew(&it, arrImag);
i=0;
while (jsvIteratorHasElement(&it)) {
jsvUnLock(jsvIteratorSetValue(&it, jsvNewFromFloat(vImag[i++])));
jsvIteratorNext(&it);
}
jsvIteratorFree(&it);
}
}