John Ermitanio
First Revision of BMA180 accelerometer to read X, Y, and Z acceleration
Dependents: BMA180_1 BMA180_2 BMA180_3 BMA180_4
Revision 0:ff755cb08068, committed 2012-08-01
- Comitter:
- jsermita
- Date:
- Wed Aug 01 20:27:16 2012 +0000
- Commit message:
- First revision of a BMA180 accelerometer library to read X, Y, and Z acceleration.
Changed in this revision
| BMA180.cpp | Show annotated file Show diff for this revision Revisions of this file |
| BMA180.h | Show annotated file Show diff for this revision Revisions of this file |
diff -r 000000000000 -r ff755cb08068 BMA180.cpp
--- /dev/null Thu Jan 01 00:00:00 1970 +0000
+++ b/BMA180.cpp Wed Aug 01 20:27:16 2012 +0000
@@ -0,0 +1,153 @@
+#include "mbed.h"
+#include "BMA180.h"
+
+Serial pc(USBTX, USBRX); // tx, rx
+
+BMA180::BMA180(PinName sdi, PinName sdo, PinName sck, PinName csb, PinName interrupt) : _csb(csb), _interrupt(interrupt), spi(sdi, sdo, sck){
+ // mosi, miso, sclk
+ _csb = 1;
+ _interrupt = 0;
+}
+
+int BMA180::validate(char id, char ver) {
+ char readID;
+ int value = 0;
+
+ readID = readReg(id);
+
+ if(readID == 3) {
+ value = 1;
+ } else {
+ pc.printf("Lost Connection");
+ value = -1;
+ }
+ return value;
+}
+
+void BMA180::initBMA180(void) {
+ char readVersion, readID;
+ char byte;
+
+ readID = readReg(CHIPID);
+ readVersion = readReg(VERSION);
+
+ if(readID == 3) {
+ pc.printf("Connected to BMA180\n\r");
+ pc.printf("BMA180 Version: %d\n\r", readVersion);
+
+ reset();
+
+ byte = readReg(CTRL_REG0);
+ byte |= 0x10; // Set bit4 to 1 to enable self test and unlock image writing
+ writeReg(CTRL_REG0, byte);
+
+ byte = readReg(DIS_I2C); // Read register
+ //pc.printf("\n\rDisable I2C Before: %0.3X ", byte);
+ byte |= 0x01; // Set bit0 to 1 for only SPI
+ writeReg(DIS_I2C, byte); // Set SPI and disable I2C as per pg 31 of datasheet
+ byte = readReg(RANGE);
+ //pc.printf("After: %0.3X", byte);
+
+ byte = readReg(RANGE); // Read register
+ //pc.printf("\n\rRange Before: %0.3X ", byte);
+ byte &= 0xFB; // Set bit3,2,1 to 010 for 2g
+ byte |= 0x02;
+ writeReg(RANGE, byte);
+ byte = readReg(RANGE);
+ //pc.printf("After: %0.3X", byte);
+
+ byte = readReg(CTRL_REG3);
+ //pc.printf("\n\rRegister 3 Before: %0.3X ", byte);
+ byte |= 0x02; // Set bit1 to 1 to enable new data interrupts
+ byte |= 0x40; // Set bit6 to 1 to enable slope mode
+ byte |= 0x80; // Set bit6 to 1 to enable slope alert
+ writeReg(CTRL_REG3, byte);
+ //pc.printf("After: %0.3X", byte);
+ pc.printf("Interrupt is enabled.");
+
+ byte = readReg(CTRL_REG0);
+ byte &= 0xEF; // Set bit4 to 0 to disable self test and lock image writing
+ writeReg(CTRL_REG0, byte);
+
+ pc.printf("\n\rBMA initialization complete.\n\r");
+
+ } else {
+ pc.printf("Not connected to BMA180! ReadVersion: %d ReadID: %d\n\r", readVersion, readID);
+ }
+}
+
+void BMA180::reset(void) {
+ writeReg(RESET, 0xB6);
+ wait_ms(10);
+ pc.printf("Soft Reset, EEPROM Copied\n\r");
+}
+
+void BMA180::readAxis(void) {
+ int x_msb, y_msb, z_msb;
+ char x_lsb, y_lsb, z_lsb;
+ short ax, ay, az;
+ float afx, afy, afz;
+
+ x_lsb = readReg(ACCXLSB); // Read X LSB register
+ x_msb = readReg(ACCXMSB); // Read X MSB register
+ ax = (x_msb << 8) | x_lsb; // Concatinate X MSB and LSB
+ ax = ax >> 2; // Remove unused first 2 LSB (16 bits to 14 bits)
+ afx = (float)ax*3/16384;
+
+ y_lsb = readReg(ACCYLSB); // Read Y LSB register
+ y_msb = readReg(ACCYMSB); // Read Y MSB register
+ ay = (y_msb << 8) | y_lsb; // Concatinate Y MSB and LSB
+ ay = ay >> 2; // Remove unused first 2 LSB
+ afy = (float)ay*3/16384;
+
+ z_lsb = readReg(ACCZLSB); // Read Z LSB register
+ z_msb = readReg(ACCZMSB); // Read Z MSB register
+ az = (z_msb << 8) | z_lsb; // Concatinate Z MSB and LSB
+ az = az >> 2; // Remove unused first 2 LSB
+ afz = (float)az*3/16384;
+
+
+ pc.printf("\n\rX: %05f Y: %05f Z: %05f", afx, afy, afz);
+}
+
+void BMA180::writeReg(uint8_t address, char data) {
+ address &= 0x7F; // Set bit7 to 0 for write mode
+ _csb = 0; // Select the device
+ wait_us(2);
+ spi.write(address); // Send to data register location
+ wait_us(2);
+ spi.write(data); // Send value to register
+ wait_us(2);
+ _csb = 1; // Deselect the device
+}
+
+char BMA180::readReg(uint8_t address) {
+ char byte;
+
+ address |= 0x80; // Set bit7 to 1 for read mode
+ _csb = 0; // Select the device
+ wait_us(2);
+ spi.write(address); // Send to data register location
+ wait_us(2);
+ byte = spi.write(address); // Get data
+ wait_us(2);
+ _csb = 1; // Deselect the device
+ wait_us(2);
+ return byte;
+}
+
+void BMA180::disInt(void) {
+ char byte;
+
+ byte = readReg(CTRL_REG0);
+ byte |= 0x10; // Set bit4 to 1 to enable self test and unlock image writing
+ writeReg(CTRL_REG0, byte);
+
+ byte = readReg(CTRL_REG3); // Unlock image writing
+ byte &= 0xFD; // Set bit1 to 0 to disable interrupt
+ writeReg(CTRL_REG3, byte);
+
+ byte = readReg(CTRL_REG0);
+ byte &= 0xEF; // Set bit4 to 0 to disable self test and lock image writing
+ writeReg(CTRL_REG0, byte);
+}
diff -r 000000000000 -r ff755cb08068 BMA180.h
--- /dev/null Thu Jan 01 00:00:00 1970 +0000
+++ b/BMA180.h Wed Aug 01 20:27:16 2012 +0000
@@ -0,0 +1,39 @@
+#include "mbed.h"
+#ifndef MBED_BMA180_H
+#define MBED_BMA180_H
+
+/******************DEFINED REGISTERS******************/
+#define CHIPID 0x00
+#define VERSION 0x01
+#define ACCXLSB 0x02
+#define ACCXMSB 0x03
+#define ACCYLSB 0x04
+#define ACCYMSB 0x05
+#define ACCZLSB 0x06
+#define ACCZMSB 0x07
+#define TEMP 0x08
+#define CTRL_REG0 0x0D
+#define BWTCS 0x20
+#define DIS_I2C 0x27 // bit0 must be 1 for SPI
+#define CTRL_REG3 0x21 // bit1 = new_data_int
+#define RESET 0x10 // soft reset
+#define RANGE 0x35 // 2g = 010
+
+class BMA180 {
+public:
+ BMA180(PinName _sdi, PinName _sdo, PinName _sck, PinName _cs, PinName _interrupt);
+ int validate(char idAddress, char verAddress);
+ void initBMA180(void);
+ void reset(void);
+ void readAxis(void);
+ void writeReg(uint8_t address, char data);
+ char readReg(uint8_t address);
+ void disInt(void);
+
+private:
+ SPI spi;
+ DigitalOut _csb;
+ DigitalOut _interrupt;
+};
+
+#endif
\ No newline at end of file