main.cpp

00001 #include "mbed.h"
00002 #include "FXOS8700CQ.h"
00003 
00004 #define DATA_RECORD_TIME_MS 1000
00005 
00006 Serial pc(USBTX, USBRX); // Primary output to demonstrate library
00007 
00008 // Pin names for FRDM-K64F
00009 FXOS8700CQ fxos(PTE25, PTE24, FXOS8700CQ_SLAVE_ADDR1); // SDA, SCL, (addr << 1)
00010 
00011 DigitalOut green(LED_GREEN); // waiting light
00012 DigitalOut blue(LED_BLUE); // collection-in-progress light
00013 DigitalOut red(LED_RED); // completed/error ligt
00014 
00015 Timer t; // Microsecond timer, 32 bit int, maximum count of ~30 minutes
00016 InterruptIn fxos_int1(PTC6); // unused, common with SW2 on FRDM-K64F
00017 InterruptIn fxos_int2(PTC13); // should just be the Data-Ready interrupt
00018 InterruptIn start_sw(PTA4); // switch SW3
00019 
00020 // Interrupt status flags and data
00021 bool fxos_int1_triggered = false;
00022 bool fxos_int2_triggered = false;
00023 uint32_t us_ellapsed = 0;
00024 bool start_sw_triggered = false;
00025 
00026 void trigger_fxos_int1(void)
00027 {
00028     fxos_int1_triggered = true;
00029 }
00030 
00031 void trigger_fxos_int2(void)
00032 {
00033     fxos_int2_triggered = true;
00034     us_ellapsed = t.read_us();
00035 }
00036 
00037 void trigger_start_sw(void)
00038 {
00039     start_sw_triggered = true;
00040 }
00041 
00042 void print_reading()
00043 {
00044     pc.printf("%d A X:%5d,Y:%5d,Z:%5d   M X:%5d,Y:%5d,Z:%5d\r\n",
00045               us_ellapsed,
00046               fxos.getAccelX(), fxos.getAccelY(), fxos.getAccelZ(),
00047               fxos.getMagnetX(), fxos.getMagnetY(), fxos.getMagnetZ());
00048 }
00049 
00050 int main(void)
00051 {
00052     // Setup
00053     t.reset();
00054     pc.baud(115200); // Print quickly! 200Hz x line of output data!
00055 
00056     // Lights off (FRDM-K64F has active-low LEDs)
00057     green.write(1);
00058     red.write(1);
00059     blue.write(1);
00060 
00061     // Diagnostic printing of the FXOS WHOAMI register value
00062     printf("\r\n\nFXOS8700Q Who Am I= %X\r\n", fxos.get_whoami());
00063 
00064     // Iterrupt for active-low interrupt line from FXOS
00065     // Configured with only one interrupt on INT2 signaling Data-Ready
00066     fxos_int2.fall(&trigger_fxos_int2);
00067     fxos.enable();
00068 
00069     // Interrupt for SW3 button-down state
00070     start_sw.mode(PullUp); // Since the FRDM-K64F doesn't have its SW2/SW3 pull-ups populated
00071     start_sw.fall(&trigger_start_sw);
00072 
00073     green.write(0); // ready-green on
00074 
00075     // Example data printing
00076     fxos.get_data();
00077     print_reading();
00078 
00079     pc.printf("Waiting for data collection trigger on SW3\r\n");
00080 
00081     while(true) {
00082         if(start_sw_triggered) {
00083             break;
00084         }
00085         wait_ms(50); // just to slow the loop, fast enough for UX
00086     }
00087 
00088     green.write(1); // ready-green off
00089     blue.write(0); // working-blue on
00090 
00091    pc.printf("Started data collection. Accelerometer at max %dg.\r\n",
00092    fxos.get_accel_scale());
00093 
00094     fxos.get_data(); // clear interrupt from device
00095     fxos_int2_triggered = false; // un-trigger
00096 
00097     t.start(); // start timer and enter collection loop
00098     while (t.read_ms() <= DATA_RECORD_TIME_MS) {
00099 
00100         if(fxos_int2_triggered) {
00101             fxos_int2_triggered = false; // un-trigger
00102             fxos.get_data();
00103             print_reading(); // outpouring of data !!
00104         }
00105 
00106         // Continuous polling of interrupt status is not efficient, but...
00107         wait_us(500); // 1/10th the period of the 200Hz sample rate
00108     }
00109 
00110     blue.write(1); // working-blue off
00111     red.write(0); // complete-red on
00112 
00113     pc.printf("Done. Reset to repeat.\r\n");
00114 
00115     while(true) {
00116         pc.putc('.'); // idle dots
00117         wait(1.0);
00118     }
00119 }