Redpitaya Forum

Posted: **Wed Jul 13, 2016 9:53 pm**

Hello,

This is my first experience with RedPitaya, so maybe my question will be easy to answer.
I have written this code in C using the functions defined in rp.h :

Code: Select all

#include [things to include]
#define [some symbolic defines]
int main(int argc, char **argv){
rp_Init();
/* generate a sine signal in OUT1 linked to IN1 */
	rp_GenReset();
	rp_GenFreq(RP_CH_1, FREQ);
	rp_GenAmp(RP_CH_1, 1);
	rp_GenWaveform(RP_CH_1, RP_WAVEFORM_SINE);
	rp_GenOutEnable(RP_CH_1);

/* set the acquisition parameters */
    uint32_t buff_size = 8000;
    float *buff = (float *)malloc(buff_size * sizeof(float));

    rp_AcqReset();
    rp_AcqSetSamplingRate(RP_SMP_125M);
    rp_AcqSetTriggerSrc(RP_TRIG_SRC_CHA_PE); // CHA positive edge
    rp_AcqSetTriggerLevel(0.1);
    
/* start the acquisition and stop it when trigger happened */
	rp_AcqStart();
	sleep(0.001); // waiting to fill the buffer
        rp_acq_trig_state_t state = RP_TRIG_STATE_WAITING;
    
    while(1){ 
		rp_AcqGetTriggerState(&state);
		if(state == RP_TRIG_STATE_TRIGGERED){
			rp_AcqStop();
			break;}
		}
            
    rp_AcqGetLatestDataV(RP_CH_1, &buff_size, buff);
    
    FILE* file;
    file = fopen("/opt/redpitaya/www/apps/output","wb");
    
    fwrite(buff,sizeof(float),buff_size,file);

    fclose(file);
    free(buff);
    rp_Release();
    return 0;
}

But sometimes my program does not trigger (does not stop), and it gives different results like these (sorry for the huge pictures, I do not know how to change their size) :

Did I do something wrong ?
Thank you,

H30X

[edit]
after some more tests, it happens that the trigger does not works as expected : sometimes, it does not change its state whereas the voltage passed trough the threshold several times. no idea why it works sometimes and sometimes it does not.

[edit]
the trigger sometimes work, and sometimes not. without any apparent reason

Redpitaya Forum

C, trigger happens sometimes not, never at the same moment

C, trigger happens sometimes not, never at the same moment