File content as of revision 10:e3d6c92ff222:

#include "mbed.h"
#include "rtos.h"
#include "I2CMasterRtos.h"
#include "stdint.h"

DigitalOut osci(p16);

volatile int g_disco=0;
volatile int g_len=0;
volatile int g_freq=100000;
const uint32_t i2cAdr = 0x68<<1;
volatile osThreadId i2cDrvThrdID;

static void config(I2CMasterRtos& i2c);

void highPrioCallBck(void const *args)
{
    osSignalSet(i2cDrvThrdID, 1<<5);
}

void highPrioThreadFun(void const *args)
{
    //printf("tst01\n");
    i2cDrvThrdID = Thread::gettid();
    I2CMasterRtos i2c(p28, p27);
    //printf("tst02\n");
    config(i2c);

    while(true) {
        osci.write(0);
        i2c.frequency(g_freq);
        Thread::signal_wait(1<<5,osWaitForever);
        // read back srf08 echo times (1+16 words)
        const char reg= 0x3a;
        char result[64];
        uint32_t t1=us_ticker_read();
        int stat = i2c.read(i2cAdr, reg, result, g_len);

        uint32_t dt=us_ticker_read()-t1;
        if(stat!=0) {
            osci.write(1);
            printf("\n%x %d %d %d\n",stat,g_freq,g_len,dt);
            exit(0);
        }
        uint16_t tm=((static_cast<uint16_t>(result[0])<<8)|static_cast<uint16_t>(result[1]));

        if(--g_disco>0) printf("tm=%8d dt=%4dus\n",tm,dt);
    }
}

int doit()
{
    Thread highPrioThread(highPrioThreadFun,0,osPriorityAboveNormal);
    RtosTimer highPrioTicker(highPrioCallBck, osTimerPeriodic, (void *)0);

    Thread::wait(100);
    highPrioTicker.start(1);

#if defined(TARGET_LPC1768)
    const int nTest=7;
    const int freq[nTest]=  {1e5,   1e5,    1e5,   4e5,    4e5,    4e5,    4e5};
    const int len[nTest]=   {1,     4,      6,      1,     6,     12,      36};
#elif defined(TARGET_LPC11U24)
    const int nTest=5;
    const int freq[nTest]=  {1e5,   1e5,    4e5,   4e5,    4e5    };
    const int len[nTest]=   {1,     4,      1,      6,     16};
#endif
    for(int i=0; i<nTest; ++i) {
        g_freq = freq[i];
        g_len = len[i];
        printf("f=%d l=%d\n",g_freq,g_len);
        Thread::wait(500);
        const uint32_t dt=1e6;
        uint32_t tStart = us_ticker_read();
        uint32_t tLast = tStart;
        uint32_t tAct = tStart;
        uint32_t tMe=0;
        do {
            tAct=us_ticker_read();
            if(tAct>tLast) {
                if(tAct==tLast+1)++tMe;
                //tLast=tAct;
            }
            tLast=tAct;
        } while(tAct-tStart<dt);
        printf("dc=%5.2f \n", 100.0*(float)tMe/dt);
        g_disco=10;
        while(g_disco>0);
    }
    return 0;
}

void readModWrite(I2CMasterRtos& i2c, uint8_t reg, uint8_t dta)
{
    //printf("rmw01\n");
    char rd1;
    int rStat1 = i2c.read(i2cAdr, reg, &rd1, 1);
    //printf("rmw02\n");
    char data[2];
    data[0]=(char)reg;
    data[1]=(char)dta;
    char rd2;
    int wStat = i2c.write(i2cAdr, data, 2);
    osDelay(100);
    int rStat2 = i2c.read(i2cAdr, reg, &rd2, 1);
    printf("%2d%2d%2d  %2x <- %2x  => %2x -> %2x \n", rStat1, wStat, rStat2, reg, dta, rd1, rd2);
}

static void config(I2CMasterRtos& i2c)
{
    uint8_t ncfg=32;
    uint8_t regs[ncfg];
    uint8_t vals[ncfg];
    int cnt=0;
    regs[cnt]=0x6b;
    vals[cnt++]=(1<<7); // pwr 1 reg //: device reset
    regs[cnt]=0x6b;
    vals[cnt++]=1; // pwr 1 reg // clock from x gyro all pwr sav modes off
    regs[cnt]=0x19;
    vals[cnt++]=0;  // sample rate divider reg  // sapmle rate = gyro rate / (1+x)
    regs[cnt]=0x1a;
    vals[cnt++]=0;// conf  reg // no ext frame sync / no dig low pass set to 1 => 8kHz Sampling
    regs[cnt]=0x1b;
    vals[cnt++]=0;// gyro conf  reg // no test mode and gyro range 250°/s
    regs[cnt]=0x1c;
    vals[cnt++]=0;// accl conf  reg // no test mode and accl range 2g
    regs[cnt]=0x23;
    vals[cnt++]=0xf<<3;// fifo conf  reg // accl + all gyro -> fifo
    regs[cnt]=0x6a;
    vals[cnt++]=(1<<2); // pwr 1 reg // fifo reset
    regs[cnt]=0x6a;
    vals[cnt++]=(1<<6); // pwr 1 reg // fifo on

    for(int i=0; i<cnt; i++)
        readModWrite(i2c, regs[i], vals[i]);
}