Diff: main.cpp

Revision:

0:8ce1608bb6f8

diff -r 000000000000 -r 8ce1608bb6f8 main.cpp
--- /dev/null	Thu Jan 01 00:00:00 1970 +0000
+++ b/main.cpp	Sat Dec 18 11:13:09 2010 +0000
@@ -0,0 +1,198 @@
+#include "mbed.h"
+#define BMA180_ID       0x00
+#define VERSION         0x01
+#define ACCXLSB         0x02
+#define ACCXMSB         0x03
+#define ACCYLSB         0x04
+#define ACCYMSB         0x05
+#define ACCZLSB         0x06
+#define ACCZMSB         0x07
+#define CTRL_REG0       0x0D
+#define DIS_I2C         0x27    // bit 0 must be 1 for SPI
+#define CTRL_REG3       0x21    // bit 1= new_data_int
+#define RESET           0x10    // soft reset
+
+/*-------------Hardware connections-------------
+By Gerrit Pathuis (gpa@quicknet.nl)
+MBA180 breakour board (sparkfun) is used
+VIO----- mbed Vout (3.3 Volt)
+SDI----- mbed mosi (p5)
+SDO----- mbed miso (p6)
+SCK----- mbed sck  (p7)
+CS------ mbed (p8)          // chip select
+INT----- mbed (p9)          // MBA give a interrupt when ready
+GND----- mbed GND (0 Volt)
+VDO----- mbed Vout (3.3 Volt)
+there are no additional external components used
+//----------------------------------------------*/
+
+SPI spi(p5,p6,p7); //mosi, miso, sclk
+DigitalOut cs(p8);
+InterruptIn event(p9);
+
+Serial pc(USBTX, USBRX); // tx, rx
+void init_SPI_BMA180(void);
+void soft_reset(void);
+void trigger(void);
+void new_data(void);
+void write_bits(char u);
+void write_reg(uint8_t address, char data);
+char read_reg(uint8_t address);
+void disable_int(void);
+
+struct sample {                 // reserve spave for 1000 samples
+    signed short x;
+    signed short y;
+    signed short z;
+    signed short t;
+} vib[1000+1];
+
+int sample_cnt;
+
+int main() {
+    int pp;
+    float xx, yy, zz;
+
+    init_SPI_BMA180();          // init the sensor
+    sample_cnt =0;              // start the counter
+    pc.printf("Start lurking  ");
+    while (sample_cnt <50) {
+        event.rise(&trigger);
+    }
+    disable_int();              // switch the BMA180 off
+    pc.printf("\n\r\nPresent the data\n\r");
+    for (pp=0; pp<50; pp +=1)  {
+        // 2^14 = 16384
+        // Range is +/1 2.0 G versnelling
+        xx = vib[pp].x/16384.0*4.0;
+        yy = vib[pp].y/16384.0*4.0;
+        zz = vib[pp].z/16384.0*4.0;
+        pc.printf("Sample %2d, Acc X= %0.4f, Y= %0.4f, Z= %0.4f \n\r", pp, xx, yy, zz);
+    }
+}
+
+void init_SPI_BMA180(void) {
+    char readVersion, readID;
+    char byte;
+    // Setup the spi for 8 bit data, high steady state clock,
+    // second edge capture, with a 10MHz clock rate
+
+    spi.frequency(10000000);        // 10 mHz page 59 of the BMA180 datasheet
+    spi.format(8,3);                // Not conform !!! page 58 of the BMA180 datasheet)
+    wait_ms(100);
+    readID = read_reg(BMA180_ID);
+    readVersion = read_reg(VERSION);
+    pc.printf("\n\r");
+    if (readID == 3) {
+        pc.printf("Connected to BMA180\n\r");
+        pc.printf("BMA180 Version %d\n\r", readVersion);
+    } else
+        pc.printf("Sorry not connected to BMA180 !!!\n\r", readID);
+
+    soft_reset();   // to copy EEprom into volatile area
+
+    //---------------------------
+    byte = read_reg(CTRL_REG0);             // Unlock image writing
+    byte |= 0x10;                           // Set bit 4
+    write_reg(CTRL_REG0,byte);              // Have to set ee_w to
+    //------------------------
+    byte= read_reg(DIS_I2C);                // read
+    byte |= 0x01;                           // set bit0 to 1, SPI only
+    write_reg(DIS_I2C, byte);               // Set spi, disable i2c, page 31
+    //-------------------------
+    byte = read_reg(CTRL_REG3);
+    byte |= 0x02;                           // set bit 1 enable interrupt
+    byte |= 0x40;                           // set bit 6 slope mode
+    byte |= 0x80;                           // set bit 6 slope alert
+    write_reg(CTRL_REG3,byte);              //
+    pc.printf("Enable interrupt bis is set ");
+    //------------------------------
+    byte = read_reg(CTRL_REG0);             // Lock image writing
+    byte &= 0xEF;                           // REset  bit 4
+    write_reg(CTRL_REG0,byte);              // Have to set ee_w to
+    //-------------------------------------------------------------------------------------
+    pc.printf("\n\rBMA init done    \n\r");
+}
+
+void soft_reset(void) {
+    // Write a soft reset
+    // to copy EEprom into volatile area, see mid page 22
+    write_reg(RESET, 0xB6);             // page 48
+    wait_ms(10);                        // wait 10 ms, see page 49
+    pc.printf("Soft reset, EEPROM copied    \n\r");
+}
+
+//-----------------READ OUT the X-Y-Z values---------------
+void trigger(void) {
+    char x_lsb, x_msb;
+    char y_lsb, y_msb;
+    char z_lsb, z_msb;
+    signed short ax, ay, az;
+
+    //------------X----------------
+    x_lsb = read_reg(ACCXLSB);
+    x_msb = read_reg(ACCXMSB);
+    ax = (x_msb << 8) |  x_lsb ;   // combineer msb en lsb
+    ax = ax >> 2;                  // Get rid of two non-value bits in LSB
+    //------------Y----------------
+    y_lsb = read_reg(ACCYLSB);
+    y_msb = read_reg(ACCYMSB);
+    ay = (y_msb << 8) | y_lsb;     // combineer msb en lsb
+    ay = ay >> 2;                  // Get rid of two non-value bits in LSB
+    //------------Z----------------
+    z_lsb = read_reg(ACCZLSB);
+    z_msb = read_reg(ACCZMSB);
+    az = (z_msb << 8) |  z_lsb;    //  combineer msb en lsb
+    az = az >> 2;                  // Get rid of two non-value bits in LSB
+
+    //----------shift into the array---------------------
+    vib[sample_cnt].x= ax;
+    vib[sample_cnt].y= ay;
+    vib[sample_cnt].z= az;
+    //---------counter------------
+    sample_cnt += 1;
+}
+
+void write_reg(uint8_t address, char data) {
+    address &= 0x7F;                        //Force a write (bit 7=0)
+    cs=0;                                   //Select SPI device
+    wait_us(2);
+    spi.write(address);                     //Send register location
+    wait_us(2);
+    spi.write(data);                        //Send value to record into register
+    wait_us(2);
+    cs=1;
+    wait_us(2);
+}
+
+char read_reg(uint8_t address) {
+    char byte;
+    address |= 0x80;                        //Force a read (bit 7=1)
+    cs=0;
+    wait_us(2);                             //Select SPI device
+    spi.write(address);                     //Send register location
+    wait_us(2);
+    byte=spi.write(0xFF);                   //Get the data
+    wait_us(2);
+    cs=1;
+    wait_us(2);
+    return byte;
+}
+
+void disable_int(void) {
+    char byte;
+    byte = read_reg(CTRL_REG0);             // Unlock image writing
+    byte |= 0x10;                           // Set bit 4
+    write_reg(CTRL_REG0,byte);              // Have to set ee_w to
+    //-------------------------
+    byte = read_reg(CTRL_REG3);
+    byte &= 0xFD;                           // REset bit 1 enable interrupt
+    write_reg(CTRL_REG3,byte);              //
+    pc.printf("\n\rDisable interrupt bis is set ");
+    //------------------------------
+    byte = read_reg(CTRL_REG0);             // Lock image writing
+    byte &= 0xEF;                           // REset  bit 4
+    write_reg(CTRL_REG0,byte);              // Have to set ee_w to
+    pc.printf("\n\rMBA180 in now switched off ");
+}
+