Diff: MMA8451Q.cpp

Revision:

0:6149091f755d

Child:

1:d2630136d51e

--- /dev/null	Thu Jan 01 00:00:00 1970 +0000
+++ b/MMA8451Q.cpp	Thu Oct 11 10:54:16 2012 +0000
@@ -0,0 +1,63 @@
+#include "MMA8451Q.h"
+
+#define REG_WHO_AM_I       0x0D
+#define REG_CTRL_REG_1     0x2A
+#define REG_OUT_X_MSB     0x01
+#define REG_OUT_Y_MSB     0x03
+#define REG_OUT_Z_MSB     0x05
+
+#define UINT14_MAX 16383
+
+MMA8451Q::MMA8451Q(PinName sda, PinName scl, int addr) : m_i2c(sda, scl), m_addr(addr) {
+    // activate the peripheral
+    uint8_t data[2] = {REG_CTRL_REG_1, 0x01};
+    write_regs(data, 2);
+}
+
+MMA8451Q::~MMA8451Q() { }
+
+uint8_t MMA8451Q::getWhoAmI() {
+    uint8_t who_am_i = 0;
+    read_regs(REG_WHO_AM_I, &who_am_i, 1);
+    return who_am_i;
+}
+
+int16_t MMA8451Q::getAccX() {
+    return getAccAxis(REG_OUT_X_MSB);
+}
+
+int16_t MMA8451Q::getAccY() {
+    return getAccAxis(REG_OUT_Y_MSB);
+}
+
+int16_t MMA8451Q::getAccZ() {
+    return getAccAxis(REG_OUT_Z_MSB);
+}
+
+void MMA8451Q::getAccAllAxis(int16_t * res) {
+    res[0] = getAccX();
+    res[1] = getAccY();
+    res[2] = getAccZ();
+}
+
+int16_t MMA8451Q::getAccAxis(uint8_t addr) {
+    int16_t acc;
+    uint8_t res[2];
+    read_regs(addr, res, 2);
+
+    acc = (res[0] << 6) | (res[1] >> 2);
+    if (acc > UINT14_MAX/2)
+        acc -= UINT14_MAX;
+
+    return acc;
+}
+
+void MMA8451Q::read_regs(int addr, uint8_t * data, int len) {
+    char t[1] = {addr};
+    m_i2c.write(m_addr, t, 1, true);
+    m_i2c.read(m_addr, (char *)data, len);
+}
+
+void MMA8451Q::write_regs(uint8_t * data, int len) {
+    m_i2c.write(m_addr, (char *)data, len);
+}