Posted on March 08, 2014 at 13:03
Hi, like another people i configure a vpc com with my stm32f3. For that i modify the demonstration example to add cdc class. But now i want to increase the com and i would like to have some explanation (and advise). At first the code :
Demo_CompassConfig();
//Waiting User Button is pressed
while
(UserButtonPressed == 0x01)
{
//Wait for data ready
while
(DataReady !=0x05)
{}
DataReady = 0x00;
//Read Compass data
Demo_CompassReadMag(MagBuffer);
Demo_CompassReadAcc(AccBuffer);
for
(i=0;i<3;i++)
AccBuffer[i] /= 0f;
fNormAcc = sqrt((AccBuffer[0]*AccBuffer[0])+(AccBuffer[1]*AccBuffer[1])+(AccBuffer[2]*AccBuffer[2]));
fSinRoll = -AccBuffer[1]/fNormAcc;
fCosRoll = sqrt(1.0-(fSinRoll * fSinRoll));
fSinPitch = AccBuffer[0]/fNormAcc;
fCosPitch = sqrt(1.0-(fSinPitch * fSinPitch));
if
( fSinRoll >0)
{
if
(fCosRoll>0)
{
RollAng = acos(fCosRoll)*180/PI;
}
else
{
RollAng = acos(fCosRoll)*180/PI + 180;
}
}
else
{
if
(fCosRoll>0)
{
RollAng = acos(fCosRoll)*180/PI + 360;
}
else
{
RollAng = acos(fCosRoll)*180/PI + 180;
}
}
if
( fSinPitch >0)
{
if
(fCosPitch>0)
{
PitchAng = acos(fCosPitch)*180/PI;
}
else
{
PitchAng = acos(fCosPitch)*180/PI + 180;
}
}
else
{
if
(fCosPitch>0)
{
PitchAng = acos(fCosPitch)*180/PI + 360;
}
else
{
PitchAng = acos(fCosPitch)*180/PI + 180;
}
}
if
(RollAng >=360)
{
RollAng = RollAng - 360;
}
if
(PitchAng >=360)
{
PitchAng = PitchAng - 360;
}
fTiltedX = MagBuffer[0]*fCosPitch+MagBuffer[2]*fSinPitch;
fTiltedY = MagBuffer[0]*fSinRoll*fSinPitch+MagBuffer[1]*fCosRoll-MagBuffer[1]*fSinRoll*fCosPitch;
HeadingValue = (
float
) ((atan2f((
float
)fTiltedY,(
float
)fTiltedX))*180)/PI;
if
(bDeviceState == CONFIGURED)
{
float_t TabKs=RollAng;
uint8_t *ptr_Ks=(uint8_t*)&TabKs;
uint8_t Lentgh_Ks=
sizeof
(TabKs);
CDC_Send_DATA(ptr_Ks, Lentgh_Ks);
STM_EVAL_LEDOn(LED6);
}
else
{
STM_EVAL_LEDOff(LED6);
}
}
UserButtonPressed = 0x00;
}
}
definition of systick in the main :
/* SysTick end of count event each 10ms */
RCC_GetClocksFreq(&RCC_Clocks);
SysTick_Config(RCC_Clocks.HCLK_Frequency / 100);
the handler :
void
SysTick_Handler(
void
)
{
TimingDelay_Decrement();
USBConnectTimeOut--;
DataReady ++;
}
If i understand the dataReady is for wait 50ms (systick interrupt every 10ms and increment a counter while dataReady is equal to 5), this mean a frequents of 20Hz. Why they define a delay of 50 ms ? If i would like to refresh the value each 10 ms, how i can proceed ? i tried to replace
while
(DataReady !=0x05)
//by
while
(DataReady !=0x01)
but after a moment (2s) i loose some data ..
How can i proceed to increase the send of data ?
