Mbed Serial Peripheral Interface( SPI) with accelerometer MMA7745L module

0 nhận xét

Summary:

Use LPC 1114 MCU and MMA7745L module .


Fig.1 LPC1114 and MMA7745L moudle
Code

#include "mbed.h"

SPI spi(dp2, dp1, dp6); // mosi, miso, sclk
DigitalOut cs(dp14);

Serial pc(dp16, dp15); // tx, rx
int8_t read(uint8_t reg){
        wait_us(100);
        cs=0;
        spi.write(reg<<1);
        int8_t val = spi.write(0x00);
        wait_us(100);
        cs=1;
        return (val);
}
void  write(uint8_t reg, uint8_t val){
        wait_us(10);
        cs=0; 
        spi.write((reg<<1)|0x80);
        spi.write(val);
        wait_us(10);
        cs=1;
}

int main() {
        wait(1);
        spi.format(8,0);
        pc.baud(9600);
        spi.frequency(3000000);
        write(0x16,0b00000101);//2g set
        wait(1);
        //offset
        write(0x10,0x11);
        write(0x12,0x34);
        write(0x14,0x2c);
        wait(1);
        float  gx,gy,gz;
        while(1){
                gx=(float)(read(0x06))/64.0*9.8;
                gy=(float)(read(0x07))/64.0*9.8;
                gz=(float)(read(0x08))/64.0*9.8;
                pc.printf("gx=%2.2f  gy=%2.2f  gz=%2.2f\n",gx,gy,gz);
                wait (0.1);
        }
}
Facebook Comments
Blogger Comments
Share knowledge

Copyright © 2016 - Share knowledge ®