Revision 0:c036efff0b10, committed 2009-11-13
- Comitter:
- simon
- Date:
- Fri Nov 13 11:58:12 2009 +0000
- Commit message:
Changed in this revision
--- /dev/null Thu Jan 01 00:00:00 1970 +0000
+++ b/LIS302.cpp Fri Nov 13 11:58:12 2009 +0000
@@ -0,0 +1,157 @@
+/* mbed LIS302 Accelerometer
+ * Copyright (c) 2008-2009 cstyles, wreynolds, sford
+ * Released under the MIT License: http://mbed.org/license/mit
+ */
+
+#include "LIS302.h"
+#include "mbed.h"
+
+#define LIS302_WHOAMI 0x0F
+#define LIS302_CTRL_REG1 0x20
+#define LIS302_CTRL_REG2 0x21
+#define LIS302_CTRL_REG3 0x22
+#define LIS302_HP_FILTER_RST 0x23
+#define LIS302_STATUS_REG 0x27
+#define LIS302_OUTX 0x29
+#define LIS302_OUTY 0x2B
+#define LIS302_OUTZ 0x2D
+#define LIS302_FF_WU_CFG1 0x30
+#define LIS302_FF_WU_SRC_1 0x31
+#define LIS302_FF_WU_THS_1 0x32
+#define LIS302_FF_WU_DURATION_1 0x33
+#define LIS302_FF_WU_CFG_2 0x34
+#define LIS302_FF_WU_SRC_2 0x35
+#define LIS302_FF_WU_THS_2 0x36
+#define LIS302_FF_WU_DURATION_2 0x37
+#define LIS302_CLICK_CFG 0x38
+#define LIS302_CLICK_SRC 0x39
+#define LIS302_CLICK_THSY_X 0x3B
+#define LIS302_CLICK_THSZ 0x3C
+#define LIS302_READ 0x80
+#define LIS302_WRITE 0x00
+
+#define LIS302_STATUS_X_AVAILABLE 0x1
+#define LIS302_STATUS_Y_AVAILABLE 0x2
+#define LIS302_STATUS_Z_AVAILABLE 0x4
+
+#define FACTOR_2g 55.6
+#define FACTOR_8g 13.9
+
+LIS302::LIS302(PinName mosi, PinName miso, PinName clk, PinName ncs)
+ : _spi(mosi, miso, clk), _ncs(ncs) {
+
+ // Make sure CS is high
+ _ncs = 1;
+
+ // Set up the spi interface
+ _spi.format(8, 3);
+ _spi.frequency(1000000);
+
+ // Write to CTRL_REG1
+ _ncs = 0;
+ _spi.write(LIS302_WRITE | LIS302_CTRL_REG1);
+ _spi.write (0x47);
+ _ncs = 1;
+
+ // Write to CTRL_REG2
+ _ncs = 0;
+ _spi.write(LIS302_WRITE | LIS302_CTRL_REG2);
+ _spi.write (0x0); // This is default anyway
+ _ncs = 1;
+
+ // Write to CTRL_REG3
+ _ncs = 0;
+ _spi.write(LIS302_WRITE | LIS302_CTRL_REG3);
+ _spi.write (0x0); // This is default anyway
+ _ncs = 1;
+
+ range(0);
+ calibrate();
+}
+
+float LIS302::x() {
+ // wait for a new sample
+ while(!(status() & LIS302_STATUS_X_AVAILABLE));
+
+ _ncs = 0;
+ _spi.write(LIS302_READ | LIS302_OUTX);
+ signed char raw = _spi.write(0x00);
+ _ncs = 1;
+
+ float gradient = (2.0/(_maxx-_minx));
+ return (gradient*(float)(raw)/_factor)+((-gradient*_maxx)+1);
+}
+
+float LIS302::y() {
+ // wait for a new sample
+ while(!(status() & LIS302_STATUS_Y_AVAILABLE));
+
+ _ncs = 0;
+ _spi.write(LIS302_READ | LIS302_OUTY);
+ signed char raw = _spi.write(0x00);
+ _ncs = 1;
+
+ float gradient = (2.0/(_maxy-_miny));
+ return (gradient*(float)(raw)/_factor)+((-gradient*_maxy)+1);
+}
+
+float LIS302::z() {
+ // wait for a new sample
+ while(!(status() & LIS302_STATUS_Z_AVAILABLE));
+
+ _ncs = 0;
+ _spi.write(LIS302_READ | LIS302_OUTZ);
+ signed char raw = _spi.write(0x00);
+ _ncs = 1;
+
+ float gradient = (2.0/(_maxz-_minz));
+ return (gradient*(float)(raw)/_factor)+((-gradient*_maxz)+1);
+}
+
+void LIS302::range(int g) {
+
+ // fetch the current CRTL_REG1
+ _ncs = 0;
+ _spi.write(LIS302_READ | LIS302_CTRL_REG1);
+ int value = _spi.write(0x00);
+ _ncs = 1;
+
+ // set the range bit, and the calculation factor
+ if(g) {
+ value |= 0x20; // 8g
+ _factor = FACTOR_8g;
+ } else {
+ value &= ~0x20; // 2g
+ _factor = FACTOR_2g;
+ }
+
+ _ncs = 0;
+ _spi.write(LIS302_WRITE | LIS302_CTRL_REG1);
+ _spi.write(value);
+ _ncs = 1;
+}
+
+void LIS302::calibrate(float maxx, float minx, float maxy, float miny, float maxz, float minz) {
+ _maxx = maxx;
+ _minx = minx;
+ _maxy = maxy;
+ _miny = miny;
+ _maxz = maxz;
+ _minz = minz;
+}
+
+int LIS302::whoami() {
+ _ncs = 0;
+ _spi.write(LIS302_READ | LIS302_WHOAMI);
+ int value = _spi.write(0x00);
+ _ncs = 1;
+ return value;
+}
+
+int LIS302::status() {
+ _ncs = 0;
+ _spi.write(0xA7);
+ int value = _spi.write(LIS302_READ | LIS302_STATUS_REG);
+ _ncs = 1;
+ return value;
+}
--- /dev/null Thu Jan 01 00:00:00 1970 +0000
+++ b/LIS302.h Fri Nov 13 11:58:12 2009 +0000
@@ -0,0 +1,101 @@
+/* mbed LIS302 Accelerometer
+ * Copyright (c) 2008-2009 cstyles, wreynolds, sford
+ * Released under the MIT License: http://mbed.org/license/mit
+ */
+
+#ifndef MBED_LIS302_H
+#define MBED_LIS302_H
+
+#include "mbed.h"
+
+/* Class: LIS302
+ * An abstraction for the LIS302 triple axis SPI accelerometer
+ *
+ * Example:
+ * > // Print out the Z axis acceleration
+ * >
+ * > #include "mbed.h"
+ * > #include "LIS302.h"
+ * >
+ * > LIS302 acc(p5, p6, p7, p8); // mosi, miso, clk, ncs
+ * >
+ * > int main() {
+ * > while(1) {
+ * > printf("Z axis acceleration = %.2f\n", acc.z());
+ * > wait(0.1);
+ * > }
+ * > }
+ */
+class LIS302 {
+public:
+
+ /* Constructor: LIS302
+ * Create an object for the LIS302, connected to the specified pins
+ *
+ * Variables:
+ * mosi - SPI data out
+ * miso - SPI data in
+ * clk - SPI clock
+ * ncs - Active low chip select. Any DigitalOut will do
+ */
+ LIS302(PinName mosi, PinName miso, PinName clk, PinName ncs);
+
+ /* Function: x
+ * Read the X axis acceleration
+ *
+ * Variables:
+ * returns - A floating-point value representing acceleration in g
+ */
+ float x();
+
+ /* Function: y
+ * Read the Y axis acceleration
+ *
+ * Variables:
+ * returns - A floating-point value representing acceleration in g
+ */
+ float y();
+
+ /* Function: z
+ * Read the Z axis acceleration
+ *
+ * Variables:
+ * returns - A floating-point value representing acceleration in g
+ */
+ float z();
+
+ /* Function: range
+ * Select the range of the accelerometer
+ *
+ * Variables:
+ * range - 0 = 2g, 1 = 8g
+ */
+ void range(int g);
+
+ /* Function: Calibrate
+ * Configure the minima and maxima for the axes to linearise the readings
+ *
+ * Variables:
+ * maxx - float defining the maximum X value
+ * minx - float defining the minimum X value
+ * maxy - float defining the maximum Y value
+ * miny - float defining the minimum Y value
+ * maxz - float defining the maximum Z value
+ * minz - float defining the minimum Z value
+ */
+ void calibrate(float maxx = 1, float minx = -1, float maxy = 1, float miny = -1, float maxz = 1, float minz = -1);
+
+private:
+ SPI _spi;
+ DigitalOut _ncs;
+
+ int whoami();
+ int status();
+
+ float _factor;
+ float _maxx, _minx;
+ float _maxy, _miny;
+ float _maxz, _minz;
+};
+
+#endif
--- /dev/null Thu Jan 01 00:00:00 1970 +0000
+++ b/main.cpp Fri Nov 13 11:58:12 2009 +0000
@@ -0,0 +1,13 @@
+// LIS302 Hello World!
+
+#include "mbed.h"
+#include "LIS302.h"
+
+LIS302 acc(p5, p6, p7, p8); // mosi, miso, sclk, ncs
+
+int main() {
+ while(1) {
+ printf("%.3f %.3f %.3f\n", acc.x(), acc.y(), acc.z());
+ wait(0.1);
+ }
+}
--- /dev/null Thu Jan 01 00:00:00 1970 +0000
+++ b/mbed.bld Fri Nov 13 11:58:12 2009 +0000
@@ -0,0 +1,1 @@
+http://mbed.org/users/mbed_official/code/mbed/builds/737756e0b479
Simon Ford