Darrel Weng
Output onboard accelerometer data of FRDM-KL25Z board on serial.
Revision 0:effa4c81f363, committed 2017-07-18
- Comitter:
- DWeng
- Date:
- Tue Jul 18 18:35:27 2017 +0000
- Commit message:
- initial commit
Changed in this revision
diff -r 000000000000 -r effa4c81f363 MMA8451Q.lib --- /dev/null Thu Jan 01 00:00:00 1970 +0000 +++ b/MMA8451Q.lib Tue Jul 18 18:35:27 2017 +0000 @@ -0,0 +1,1 @@ +https://developer.mbed.org/users/DWeng/code/MMA8451Q/#9c229882cd2b
diff -r 000000000000 -r effa4c81f363 main.cpp
--- /dev/null Thu Jan 01 00:00:00 1970 +0000
+++ b/main.cpp Tue Jul 18 18:35:27 2017 +0000
@@ -0,0 +1,84 @@
+/**
+ * +----------------------+
+ * | Accelerometer Output |
+ * +----------------------+
+ *
+ * Sample accelerometer at x Hz and output data onto serial port. Used for
+ * UC Merced data acquisition and filtering project.
+ *
+ * Leverages Antonio Quevedo's MMA8451Q library for interfacing with the
+ * accelerometer over I2C, with slight modification to configuration.
+ *
+ * Acceleration should be sampled no faster than 800Hz, but we will output at
+ * 100Hz. -- ADD ODR MODIFIER
+ *
+ * Output Data Packet:
+ * [ start_byte, acc_xH, acc_xL, acc_yH, acc_yL, acc_zH, acc_zL, checksum1, checksum2, end_byte ]
+ *
+ * Output all axes, but really only interested in y and z axes.
+ *
+ * Darrel Weng
+ *
+ */
+
+#include "mbed.h"
+#include "MMA8451Q.h"
+
+#include <string.h>
+
+int period = 8; // data reads before output; set at 50Sps
+int acc_flag = 0; // flag to super loop to read data
+int flag_count = 0; // counter for how many times data has been read
+
+void
+mma8451q_int()
+{
+ acc_flag = 1;
+}
+
+int main()
+{
+ /* objects */
+ DigitalOut laser(PTE2);
+ Serial pc(USBTX, USBRX);
+ //Timer timer;
+ MMA8451Q acc(PTE25, PTE24);
+ InterruptIn accINT1(PTA14);
+
+ /* init */
+ laser = 0; // turn laser on; pin is active sinking
+ pc.baud(115200); // high baudrate for lower latency comm
+ accINT1.fall(&mma8451q_int);
+
+ /* local variables */
+ int16_t acc_data[4]; // 4th entry contains checksum
+ uint8_t output[10];
+
+ /* Start and Stop delimiting Bytes */
+ output[0] = 0xBE;
+ output[9] = 0xEF;
+
+ while(1)
+ {
+ // if data ready, read data
+ if (acc_flag)
+ {
+ acc_flag = 0;
+ acc.getAccAllAxis(acc_data);
+ for (int i=0;i<3;i++)
+ acc_data[i] /= 4;
+ flag_count++;
+ }
+ // if time to output
+ if (flag_count >= period)
+ {
+ flag_count = 0;
+ //pc.printf("%d %d %d \r\n", acc_data[0], acc_data[1], acc_data[2]);
+ // Build packet
+ acc_data[3] = acc_data[0] + acc_data[1] - acc_data[2];
+ memcpy(output+1, acc_data, 8);
+ for (int i=0; i<10; i++)
+ pc.putc(output[i]);
+ }
+ }
+}
diff -r 000000000000 -r effa4c81f363 mbed.bld --- /dev/null Thu Jan 01 00:00:00 1970 +0000 +++ b/mbed.bld Tue Jul 18 18:35:27 2017 +0000 @@ -0,0 +1,1 @@ +http://mbed.org/users/mbed_official/code/mbed/builds/b0220dba8be7 \ No newline at end of file