I2CDriverTest04.h

00001 // A high prio thread reads at a rate of 1kHz from a MPU6050 gyro/acc meter's FIFO
00002 // data packets of different size, whereas the lower prio ain thread the CPU time left.
00003 
00004 #include "mbed.h"
00005 #include "rtos.h"
00006 #include "I2CMasterRtos.h"
00007 #include "stdint.h"
00008 
00009 //#include "DigitalOut.h"
00010 //DigitalOut osci(p8);
00011 
00012 volatile int g_disco=0;
00013 volatile int g_len=0;
00014 volatile int g_freq=100000;
00015 const uint32_t i2cAdr = 0x68<<1;
00016 
00017 static void config(I2CMasterRtos& i2c);
00018 
00019 I2CMasterRtos i2c(p28, p27);
00020 
00021 void highPrioCallBck(void const *args)
00022 {
00023     //I2CDriver::osci2.write(0);
00024     const char reg= 0x74;
00025     static char result[64];
00026     //I2CDriver::osci2.write(1);
00027     // read from MPU600's fifo
00028     i2c.frequency(g_freq);
00029     uint32_t t1=us_ticker_read();
00030     //I2CDriver::osci2.write(0);
00031     int stat = i2c.read(i2cAdr, reg, result, g_len);
00032     uint32_t dt=us_ticker_read()-t1;
00033     if(stat!=0) {
00034         printf("\n%x %d %d %d\n",stat,g_freq,g_len,dt);
00035         exit(0);
00036     }
00037     int16_t val=((static_cast<int16_t>(result[0])<<8)|static_cast<int16_t>(result[1]));
00038 
00039     if(--g_disco>0)printf("val=%8d dt=%4dus\n",val,dt);
00040 }
00041 
00042 int doit()
00043 {
00044     config(i2c);
00045     
00046     RtosTimer highPrioTicker(highPrioCallBck, osTimerPeriodic, (void *)0);
00047 
00048     Thread::wait(500);
00049     highPrioTicker.start(1);
00050 
00051 #if defined(TARGET_LPC1768)
00052     const int nTest=7;
00053     const int freq[nTest]=  {1e5,   1e5,    1e5,   4e5,    4e5,    4e5,    4e5};
00054     const int len[nTest]=   {1,     4,      7,      1,     6,     12,      36};
00055 #elif defined(TARGET_LPC11U24)
00056     const int nTest=5;
00057     const int freq[nTest]=  {1e5,   1e5,    4e5,   4e5,    4e5    };
00058     const int len[nTest]=   {1,     6,      1,      6,     32};
00059 #endif
00060     for(int i=0; i<nTest; ++i) {
00061         g_freq = freq[i];
00062         g_len = len[i];
00063         printf("f=%d l=%d\n",g_freq,g_len);
00064         Thread::wait(500);
00065         //highPrioTicker.start(1);
00066         const uint32_t dt=1e6;
00067         uint32_t tStart = us_ticker_read();
00068         uint32_t tLast = tStart;
00069         uint32_t tAct = tStart;
00070         uint32_t tMe=0;
00071         do {  // loop an count consecutive µs ticker edges
00072             //osci.write(!osci.read());
00073             tAct=us_ticker_read();
00074             #if defined(TARGET_LPC1768)
00075             if(tAct==tLast+1)++tMe;
00076             #elif defined(TARGET_LPC11U24)
00077             uint32_t delta = tAct-tLast;
00078             if(delta<=2)tMe+=delta;  // on the 11U24 this loop takes a bit longer than 1µs (ISR ~3µs, task switch ~8µs)
00079             #endif
00080             tLast=tAct;
00081         } while(tAct-tStart<dt);
00082         //highPrioTicker.stop();
00083         // and calculate the duty cycle from this measurement
00084         printf("dc=%5.2f \n", 100.0*(float)tMe/dt);
00085         g_disco=5;
00086         while(g_disco>0);
00087     }
00088     return 0;
00089 }
00090 
00091 void readModWrite(I2CMasterRtos& i2c, uint8_t reg, uint8_t dta)
00092 {
00093     char rd1;
00094     int rStat1 = i2c.read(i2cAdr, reg, &rd1, 1);
00095     char data[2];
00096     data[0]=(char)reg;
00097     data[1]=(char)dta;
00098     char rd2;
00099     int wStat = i2c.write(i2cAdr, data, 2);
00100     osDelay(100);
00101     int rStat2 = i2c.read(i2cAdr, reg, &rd2, 1);
00102     printf("(%3x%3x%3x)  %2x <- %2x  => %2x -> %2x \n", rStat1, wStat, rStat2, reg, dta, rd1, rd2);
00103 }
00104 
00105 static void config(I2CMasterRtos& i2c)
00106 {
00107     uint8_t ncfg=32;
00108     uint8_t regs[ncfg];
00109     uint8_t vals[ncfg];
00110     int cnt=0;
00111     regs[cnt]=0x6b;
00112     vals[cnt++]=(1<<7); // pwr 1 reg //: device reset
00113     regs[cnt]=0x6b;
00114     vals[cnt++]=1; // pwr 1 reg // clock from x gyro all pwr sav modes off
00115     regs[cnt]=0x19;
00116     vals[cnt++]=0;  // sample rate divider reg  // sapmle rate = gyro rate / (1+x)
00117     regs[cnt]=0x1a;
00118     vals[cnt++]=0;// conf  reg // no ext frame sync / no dig low pass set to 1 => 8kHz Sampling
00119     regs[cnt]=0x1b;
00120     vals[cnt++]=0;// gyro conf  reg // no test mode and gyro range 250°/s
00121     regs[cnt]=0x1c;
00122     vals[cnt++]=0;// accl conf  reg // no test mode and accl range 2g
00123     regs[cnt]=0x23;
00124     vals[cnt++]=0xf<<3;// fifo conf  reg // accl + all gyro -> fifo
00125     regs[cnt]=0x6a;
00126     vals[cnt++]=(1<<2); // pwr 1 reg // fifo reset
00127     regs[cnt]=0x6a;
00128     vals[cnt++]=(1<<6); // pwr 1 reg // fifo on
00129 
00130     for(int i=0; i<cnt; i++)
00131         readModWrite(i2c, regs[i], vals[i]);
00132 }