Revision 0:6bd5123ecef8, committed 2014-12-29

Comitter:

summers

Date:

Mon Dec 29 16:19:02 2014 +0000

Commit message:

FRDM KL25Z code that sets the LED colour dependent on the angle of the board. Demo code on how to read the I2C interface for the accelerometer. Check out the acclv2 version of this code - basically the same, but written in c++, compiles to same size

Changed in this revision

diff -r 000000000000 -r 6bd5123ecef8 main.c
--- /dev/null	Thu Jan 01 00:00:00 1970 +0000
+++ b/main.c	Mon Dec 29 16:19:02 2014 +0000
@@ -0,0 +1,117 @@
+// #include "mbed.h"
+#include "device.h"
+#include "PinNames.h"
+#include "PeripheralNames.h"
+#include "i2c_api.h"
+#include "wait_api.h"
+#include "pwmout_api.h"
+#include "rtc_api.h"
+#include <stdio.h>
+#include <math.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 MMA8451_I2C_ADDRESS (0x1d<<1)
+
+#define UINT14_MAX        16384
+
+#define false 0
+#define true -1
+
+static const float redx=0.0f;
+static const float redy=1.0f;
+static const float greenx=0.8660254f;
+static const float greeny=-0.5f;
+static const float bluex=-0.8660254f;
+static const float bluey=-0.5f;
+
+static const float twothirds=0.6666667f;
+
+void acclninit(i2c_t *i2c)
+{
+  // set the i2c link pins SDA, SCL
+  i2c_init(i2c,PTE25,PTE24);
+
+  // initialise the accelerometer
+  {
+    // REG_CTRL_REG_1 goes into the device Program Counter
+    // then 1 gets written to that address
+    uint8_t data[2] = {REG_CTRL_REG_1, 0x01};
+    i2c_write(i2c,MMA8451_I2C_ADDRESS,(char *)data,2,true);
+  }
+  
+  // read the who am i register
+  {
+    // this sets the pointer in the I2C decice (accelerometer)
+    // to point to the who_am_i register
+    // REG_WHO_AM_I gets writtem to device Program Counter
+    // We don't reset the device at the end (false)
+    char t[1] = {REG_WHO_AM_I};
+    i2c_write(i2c,MMA8451_I2C_ADDRESS,t,1,false);
+    // and this reads the register
+    uint8_t who_am_i = 0;
+    i2c_read(i2c,MMA8451_I2C_ADDRESS,(char *)&who_am_i,1,true);
+    printf("\r\nMMA8451 ID: %d\r\n", who_am_i );
+  }
+}  
+
+float acclnread(i2c_t *i2c,uint8_t reg)
+{
+  char t[1]= {reg};
+  i2c_write(i2c,MMA8451_I2C_ADDRESS,t,1,false);
+  uint8_t xbits[2] = {0,0};
+  i2c_read(i2c,MMA8451_I2C_ADDRESS,(char *)xbits,2,true);
+  int16_t xint = 0;
+  xint=(xbits[0]<<6)|(xbits[1]>>2);
+  if (xint > UINT14_MAX>>1)
+    xint -= UINT14_MAX;
+  return ((float) xint)/4096.0f;
+}
+
+
+
+int main(void)
+{
+  //  typedef struct i2c_s i2c;
+  i2c_t i2c;
+
+  acclninit(&i2c);
+
+  pwmout_t redled;
+  pwmout_t greenled;
+  pwmout_t blueled;
+
+  pwmout_init(&redled,LED_RED);
+  pwmout_period_ms(&redled,1);
+  pwmout_init(&greenled,LED_GREEN);
+  pwmout_period_ms(&greenled,1);
+  pwmout_init(&blueled,LED_BLUE);
+  pwmout_period_ms(&blueled,1);
+
+  rtc_init();
+  
+  while (true)
+    {
+      float xaccln=acclnread(&i2c,REG_OUT_X_MSB);
+      float yaccln=acclnread(&i2c,REG_OUT_Y_MSB);
+      float zaccln=acclnread(&i2c,REG_OUT_Z_MSB);
+      printf("xaccln: %f yaccln: %f zaccln: %f Time: %d\r\n",
+	     xaccln,yaccln,zaccln,rtc_read());
+      float norm=sqrt(xaccln*xaccln+yaccln*yaccln);
+      float xacclnorm=xaccln/norm;
+      float yacclnorm=yaccln/norm;
+      float rvec=xacclnorm*redx+yacclnorm*redy;
+      float gvec=xacclnorm*greenx+yacclnorm*greeny;
+      float bvec=xacclnorm*bluex+yacclnorm*bluey;
+      pwmout_write(&redled,twothirds*(1.0f-rvec));
+      pwmout_write(&greenled,twothirds*(1.0f-gvec));
+      pwmout_write(&blueled,twothirds*(1.0f-bvec));
+      wait(0.1f);
+  }
+
+}
+

diff -r 000000000000 -r 6bd5123ecef8 mbed.bld
--- /dev/null	Thu Jan 01 00:00:00 1970 +0000
+++ b/mbed.bld	Mon Dec 29 16:19:02 2014 +0000
@@ -0,0 +1,1 @@
+http://mbed.org/users/mbed_official/code/mbed/builds/4fc01daae5a5
\ No newline at end of file