GOPA KUMAR K C
Gyro_MPU3300
Diff: main.cpp
- Revision:
- 0:7e0ed4a0d584
--- /dev/null Thu Jan 01 00:00:00 1970 +0000
+++ b/main.cpp Fri Feb 13 17:17:15 2015 +0000
@@ -0,0 +1,175 @@
+#include<mbed.h>
+#include "MPU3300.h" //header file which includes all the register addresses and
+ //Bit configuration of those registers
+SPI spi (PTD6,PTD7,PTD5) ; // MOSI,MISO, CLOCK pins being used on //microcontroller(in order)
+DigitalOut ssn (PTA13); //Slave Select pin
+Serial pc(USBTX,USBRX);
+InterruptIn dr(PTD2); //Interrupt pin
+Ticker tr; //Ticker function to give values for limited amount of time
+uint8_t trFlag; //ticker Flag
+uint8_t drFlag; //data-ready interrupt flag
+void trSub();
+void drSub();
+void init_gyro();
+void execute_gyro();
+int main(void)
+{
+ init_gyro(); //Initializing Gyroscope registers and setting them to our required configuration
+ execute_gyro(); //Executing gyroscope for measuring angular rates
+ return 0;
+}
+void drSub() //In this function we setting data-ready flag to 1
+{
+ drFlag=1;
+}
+void trSub() //In this function we are setting ticker flag to 0
+{
+ trFlag=0;
+}
+void init_gyro()
+{
+ uint8_t response;
+ ssn=1; //Deselecting the chip
+ spi.format(8,3); // Spi format is 8 bits, and clock mode 3
+ spi.frequency(1000000); //frequency to be set as 1MHz
+ drFlag=0; //Intially defining data-ready flag to be 0
+ dr.mode(PullDown);
+ dr.rise(&drSub);
+ __disable_irq();
+
+/*Following the above mentioned algorithm for initializing the register and changing its configuration*/
+ ssn=0; //Selecting chip(Mpu-3300)
+ spi.write(USER_CTRL|READFLAG); //sending USER_CTRL address with read bit
+ response=spi.write(DUMMYBIT); //sending dummy bit to get default values of the register
+
+ ssn=1; //Deselecting the chip
+ wait(0.1); //waiting according the product specifications
+
+ ssn=0; //again selecting the chip
+ spi.write(USER_CTRL); //sending USER_CTRL address without read bit
+ spi.write(response|BIT_I2C_IF_DIS); //disabling the I2C mode in the register
+ ssn=1; //deselecting the chip
+ wait(0.1); // waiting for 100ms before going for another register
+
+ ssn=0;
+ spi.write(PWR_MGMT_1|READFLAG); //Power Management register-1
+ response=spi.write(DUMMYBIT);
+ ssn=1;
+ wait(0.1);
+
+ ssn=0;
+ spi.write(PWR_MGMT_1);
+ response=spi.write(response|BIT_CLKSEL_X); //Selecting the X axis gyroscope as clock as mentioned above
+ ssn=1;
+ wait(0.1);
+
+ ssn=0;
+ spi.write(GYRO_CONFIG|READFLAG); //sending GYRO_CONFIG address with read bit
+ response=spi.write(DUMMYBIT);
+ ssn=1;
+ wait(0.1);
+
+ ssn=0;
+ spi.write(GYRO_CONFIG); //sending GYRO_CONFIG address to write to register
+ spi.write(response&(~(BITS_FS_SEL_3|BITS_FS_SEL_4))); //selecting a full scale mode of +/=225 deg/sec
+ ssn=1;
+ wait(0.1);
+
+ ssn=0;
+ spi.write(CONFIG|READFLAG); //sending CONFIG address with read bit
+ response=spi.write(DUMMYBIT);
+ ssn=1;
+ wait(0.1);
+
+ ssn=0;
+ spi.write(CONFIG); //sending CONFIG address to write to register
+ spi.write(response|BITS_DLPF_CFG); //selecting a bandwidth of 42 hz and delay of 4.8ms
+ ssn=1;
+ wait(0.1);
+
+ ssn=0;
+ spi.write(SMPLRT_DIV|READFLAG); //sending SMPLRT_DIV address with read bit
+ response=spi.write(DUMMYBIT);
+ ssn=1;
+ wait(0.1);
+
+ ssn=0;
+ spi.write(SMPLRT_DIV); //sending SMPLRT_DIV address to write to register
+ spi.write(response&BITS_SMPLRT_DIV); //setting the sampling rate division to be 0 to make sample rate = gyroscopic output rate
+ ssn=1;
+ wait(0.1);
+
+ ssn=0;
+ spi.write(INT_ENABLE|READFLAG); //sending address of INT_ENABLE with readflag
+ response=spi.write(DUMMYBIT); //sending dummy byte to get the default values of the
+ // regiser
+ ssn=1;
+ wait(0.1);
+
+ ssn=0;
+ spi.write(INT_ENABLE); //sending INT_ENABLE address to write to register
+ spi.write(response|BIT_DATA_RDY_ENABLE); //Enbling data ready interrupt
+ ssn=1;
+ wait(0.1);
+
+ __enable_irq();
+}
+
+void execute_gyro()
+{
+ uint8_t response;
+ uint8_t MSB,LSB;
+ int16_t bit_data;
+ float data[3],error[3]={0,0,0}; //declaring error array to add to the values when required
+ float senstivity = 145.6; //senstivity is 145.6 for full scale mode of +/-225 deg/sec
+ ssn=0;
+ spi.write(PWR_MGMT_1|READFLAG); //sending address of INT_ENABLE with readflag
+ response=spi.write(DUMMYBIT); //
+ ssn=1;
+ wait(0.1);
+
+ ssn=0;
+ spi.write(PWR_MGMT_1); //sending PWR_MGMT_1 address to write to register
+ response=spi.write(response&(~(BIT_SLEEP))); //waking up the gyroscope from sleep
+ ssn=1;
+ wait(0.1);
+
+ trFlag=1;
+ tr.attach(&trSub,1); //executes the function trSub afer 1sec
+ while(trFlag)
+ {
+ if(drFlag==1)
+ {
+ ssn=0;
+ spi.write(GYRO_XOUT_H|READFLAG); //sending address of PWR_MGMT_1 with readflag
+ for(int i=0;i<3;i++)
+ {
+ MSB = spi.write(DUMMYBIT); //reading the MSB values of x,y and z respectively
+ LSB = spi.write(DUMMYBIT); //reading the LSB values of x,y and z respectively
+ bit_data= ((int16_t)MSB<<8)|LSB; //concatenating to get 16 bit 2's complement of the required gyroscope values
+ data[i]=(float)bit_data;
+ data[i]=data[i]/senstivity; //dividing with senstivity to get the readings in deg/sec
+ data[i]+=error[i]; //adding with error to remove offset errors
+ }
+ ssn=1;
+ for (int i=0;i<3;i++)
+ {
+ printf("%f\t",data[i]); //printing the angular velocity values
+ }
+ printf("\n");
+ break;
+ }
+ drFlag=0;
+ }
+ ssn=0;
+ spi.write(PWR_MGMT_1|READFLAG); //sending address of PWR_MGMT_1 with readflag
+ response=spi.write(DUMMYBIT);
+ ssn=1;
+ wait(0.1);
+
+ ssn=0;
+ spi.write(PWR_MGMT_1); //sending PWR_MGMT_1 address to write to register
+ response=spi.write(response|BIT_SLEEP); //setting the gyroscope in sleep mode
+ ssn=1;
+ wait(0.1);
+}