Revision 0:c036efff0b10, committed 2009-11-13

Comitter:

simon

Date:

Fri Nov 13 11:58:12 2009 +0000

Commit message:

Changed in this revision

diff -r 000000000000 -r c036efff0b10 LIS302.cpp
--- /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;
+}

diff -r 000000000000 -r c036efff0b10 LIS302.h
--- /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

diff -r 000000000000 -r c036efff0b10 main.cpp
--- /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);
+    }
+}

diff -r 000000000000 -r c036efff0b10 mbed.bld
--- /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