Problems encounterd when trying to convert double to string

Posted on June 24, 2014 at 17:07

Hi,

i recently started a school project regarding orientation using MEMS sensors. I own a MPU6050, and a fusion alrogithm already known developed by Sebastian Madgwick. Here is my code, and i will explain . i tryied do a translation from here http://mbed.org/users/aberk/code/IMUfilter_RPYExample/ to IAR 6.30, and tryied to show the angles on a plain 20x4 LCD Setup 2 timers interupts, one at 200hz, and the other at 10hz Sensors are sampled at 200hz, and the filter is sampled at 10hz. The problem apears when i try to convert the values to strings, for example sprint(tyaw,''%f'', dyaw); it returns me -nan, all 3 strings returns -nan on display. I cant understand why? Tryied even to declare dyaw as float, but the same -nan apears. Also try do integrate a ''Display function'' wich do all the string conversions, and include`it in the imufilter clas, and the problems is stil there Is there a problem in my timer routines? i cant understand why. The comunication with MPU is ok, saw`it with a logic analizyer, and is there... Thanks Why is it showing -nan ?

int main(){
SystemInit(); ///// Initialize System Clocks and PLLs 
SysTick_Init(); 
lcd_init(); // init display
mpu_I2Cinit(); 
delay_nms(100);
mpu_init();
delay_nms(100);
calibrateAccelerometer(); // take samples of acc then average
delay_nms(30); 
calibrateGyroscope(); // take samples of gyro, then avarage
delay_nms(30);
RCC_APB1PeriphClockCmd(RCC_APB1Periph_TIM2 | RCC_APB1Periph_TIM3, ENABLE);
// timer 2 setup to generate every 10ms ( 10hz) interrupt
TIM_InitStruct.TIM_Prescaler = 2000 - 1; 
TIM_InitStruct.TIM_CounterMode = TIM_CounterMode_Up; 
TIM_InitStruct.TIM_Period = 4200 - 1; //105 
TIM_InitStruct.TIM_ClockDivision = TIM_CKD_DIV1; 
TIM_InitStruct.TIM_RepetitionCounter = 0; 
TIM_TimeBaseInit(TIM2, &TIM_InitStruct);
TIM_ITConfig(TIM2, TIM_IT_Update, ENABLE);
TIM_Cmd(TIM2, ENABLE); 
// timer 3 setup to generate every 2.5ms ( 200hz) interrupts
TIM_InitStruct.TIM_Prescaler = 2000 - 1;
TIM_InitStruct.TIM_CounterMode = TIM_CounterMode_Up; 
TIM_InitStruct.TIM_Period = 210 - 1; 
TIM_InitStruct.TIM_ClockDivision = TIM_CKD_DIV1; 
TIM_InitStruct.TIM_RepetitionCounter = 0; 
TIM_TimeBaseInit(TIM3, &TIM_InitStruct);
TIM_ITConfig(TIM3, TIM_IT_Update, ENABLE); 
TIM_Cmd(TIM3, ENABLE); 
// interrupt priority for timer 2
NVIC_InitStructure.NVIC_IRQChannel = TIM2_IRQn;
NVIC_InitStructure.NVIC_IRQChannelPreemptionPriority = 0;
NVIC_InitStructure.NVIC_IRQChannelSubPriority = 1;
NVIC_InitStructure.NVIC_IRQChannelCmd = ENABLE;
NVIC_Init(&NVIC_InitStructure); 
// interrupt priority for timer 3 
NVIC_InitStructure.NVIC_IRQChannel = TIM3_IRQn;
NVIC_InitStructure.NVIC_IRQChannelPreemptionPriority =0;
NVIC_InitStructure.NVIC_IRQChannelSubPriority = 1;
NVIC_InitStructure.NVIC_IRQChannelCmd = ENABLE;
NVIC_Init(&NVIC_InitStructure); 
char troll[10];
char tpitch[10];
char tyaw[10];
while(1){ 
double droll = toDegrees(imuFilter.getRoll()); // read roll after euler computation 
double dpitch = toDegrees(imuFilter.getPitch()); // read pitch after euler computation 
double dyaw = toDegrees(imuFilter.getYaw()); // read yaw after euler computation 
sprintf(troll,''%f'', droll); // convert to string
sprintf(tpitch,''%f'', dpitch); // convert to string
sprintf(tyaw,''%f'', dyaw); // convert to string
lcd_char(1,1,troll); // display troll angle
lcd_char(2,1,tpitch); // display pitch angle
lcd_char(3,1,tyaw); // display yaw angle
}}
#ifdef __cplusplus
extern ''C'' {
#endif
//delay_nms(1);
void SysTick_Handler(void) {
TimeTick_Decrement();
}
void TIM3_IRQHandler(void){ // 200hz
if (TIM_GetITStatus(TIM3, TIM_IT_Update) != RESET)
{ 
sampleAccelerometer(); // sample accelerometor sensors (x,y,z)
sampleGyroscope(); // sample gyroscopes sensors (x,y,z)
TIM_ClearITPendingBit(TIM3, TIM_IT_Update); } }
void TIM2_IRQHandler(void){ // 10hz
if (TIM_GetITStatus(TIM2, TIM_IT_Update) != RESET)
{ 
//Update the filter variables.
imuFilter.updateFilter(w_y, w_x, w_z, a_y, a_x, a_z); // updateing filter with values from gyro & acc sampled @ timer 3 rate
//Calculate the new Euler angles. from updatefilter equations
imuFilter.computeEuler();
TIM_ClearITPendingBit(TIM2, TIM_IT_Update); } }
#ifdef __cplusplus
}
#endif