Preston Stephens / Mbed 2 deprecated Mini_Project_Day_8_Level

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Dependencies:   UniGraphic mbed

acc.cpp@5:98ad3701ec24, 2016-01-14 (annotated)

Committer:
asloop18
Date:
Thu Jan 14 22:03:54 2016 +0000
Revision:
5:98ad3701ec24
Parent:
3:824764571657
Child:
6:459d1eb2cc23
accelerometer functions defined, untested

Who changed what in which revision?

UserRevisionLine numberNew contents of line
asloop18 3:824764571657 1 /* Program 7.4: Read ADXL345 accelerometer through SPI.
asloop18 3:824764571657 2 Outputs continuously to terminal
asloop18 3:824764571657 3 */
asloop18 3:824764571657 4
asloop18 3:824764571657 5 #include "mbed.h"
asloop18 3:824764571657 6
asloop18 3:824764571657 7 SPI acc(p11,p12,p13); //Set up SPI MOSI, MISO, SCL
asloop18 5:98ad3701ec24 8 DigitalOut cs(p10); //set up chip select
asloop18 3:824764571657 9 Serial pc(USBTX, USBRX);
asloop18 3:824764571657 10 char buffer[6]; //raw filler data
asloop18 3:824764571657 11 int16_t data[3]; //16bit twos-compliment integer data
asloop18 3:824764571657 12 float x,y,z; //set up floats for values to display
asloop18 3:824764571657 13
asloop18 5:98ad3701ec24 14 void acc_init(void){
asloop18 3:824764571657 15 cs=1; //initially off
asloop18 3:824764571657 16 acc.format(8,3); //8bit, mode 3
asloop18 3:824764571657 17 acc.frequency(2000000); //2MHz
asloop18 3:824764571657 18 cs=0; //select
asloop18 3:824764571657 19 acc.write(0x31); //data format register
asloop18 3:824764571657 20 acc.write(0x0B); //+/-16g, 0.004g sensitivity
asloop18 3:824764571657 21 cs=1; //end transmission
asloop18 3:824764571657 22 cs=0; //start new transmission
asloop18 3:824764571657 23 acc.write(0x2D); //power mode = measure
asloop18 3:824764571657 24 acc.write(0x08);
asloop18 3:824764571657 25 cs=1;
asloop18 5:98ad3701ec24 26 }
asloop18 5:98ad3701ec24 27
asloop18 5:98ad3701ec24 28 float acc_sense(char axis){
asloop18 5:98ad3701ec24 29 cs=0;
asloop18 5:98ad3701ec24 30 acc.write(0x80|0x40|0x32); //RW bit high, MB bit high, address to ask for a reading
asloop18 5:98ad3701ec24 31 for (int i=0;i<=5;i++){buffer[i]=acc.write(0x00);} //read 6bytes
asloop18 5:98ad3701ec24 32 cs=1;
asloop18 5:98ad3701ec24 33 data[0]=buffer[1]<<8|buffer[0]; //x
asloop18 5:98ad3701ec24 34 data[1]=buffer[3]<<8|buffer[2]; //y combine MSB and LSB
asloop18 5:98ad3701ec24 35 data[2]=buffer[5]<<8|buffer[4]; //z
asloop18 3:824764571657 36
asloop18 5:98ad3701ec24 37 x=atan(data[0],data[2]);
asloop18 5:98ad3701ec24 38 y=atan(data[1],data[2]);
asloop18 5:98ad3701ec24 39
asloop18 5:98ad3701ec24 40 if(axis==1) return x; //if asked for x, give x
asloop18 5:98ad3701ec24 41 if(axis==2) return y; //if asked for y, give y
asloop18 3:824764571657 42 }