Add rotation of value vector for high-g-accelerometer

src/drivers/ao_adxl375.c

@@ -85,13 +85,42 @@ ao_adxl375_reg_write(uint8_t addr, uint8_t value)
 static void
 ao_adxl375_value(struct ao_adxl375_sample *value)
 {
-	uint8_t	d[7];
+	uint8_t	d[7];  
+	float magic_number = (float)0.70710678118654752440084436210484; // 1/sqrt(2); could use double for higher percision 
+	struct ao_adxl375_sample sample;
+	struct ao_adxl375_sample result;
+
 
 	d[0] = AO_ADXL375_DATAX0 | AO_ADXL375_READ | AO_ADXL375_MULTI_BYTE;
 	ao_adxl375_start();
 	ao_spi_duplex(d, d, 7, AO_ADXL375_SPI_INDEX);
 	ao_adxl375_stop();
-	memcpy(value, &d[1], 6);
+
+	memcpy(&sample, &d[1], 6);
+
+// rotating x and y by 45 degree
+
+	/* Bias by 32768 to convert from uint16_t to int16_t */
+//	sample.x = (int16_t) ((((uint16_t) raw.x0 << 8) | raw.x1) - 32768);
+//	sample.y = (int16_t) ((((uint16_t) raw.y0 << 8) | raw.y1) - 32768);
+
+//	sample.x = (int16_t) ((((uint16_t) d[2] << 8) | d[3]) - 0);
+//	sample.y = (int16_t) ((((uint16_t) d[4] << 8) | d[5]) - 0);
+//	sample.z = (int16_t) ((((uint16_t) d[6] << 8) | d[7]) - 0);
+
+	// rotate value vector by 45 degrees mathimatical positive around z-axis
+	result.x = (int16_t)((sample.x - sample.y) * magic_number);
+	result.y = (int16_t)((sample.x + sample.y) * magic_number);
+	result.z = sample.z;
+	
+//	result.x = 0;
+//	result.y = 1;
+//	result.z = sample.z;
+
+
+	memcpy(value, &result, 6);
+
+//	memcpy(value, &d[1], 6);
 }
 
 struct ao_adxl375_total {