void render(BelaContext *context, void *userData)
{
for(unsigned int n = 0; n<context->digitalFrames; n++){
gTriggerCount++;
if(gTriggerCount == gTriggerInterval){
gTriggerCount = 0;
analogWriteOnce(context, n / 2, gTriggerAnalogOutChannel, HIGH); //write the status to the trig pin
} else {
analogWriteOnce(context, n / 2, gTriggerAnalogOutChannel, LOW); //write the status to the trig pin
}
int pulseLength = pulseIn.hasPulsed(context, n); // will return the pulse duration(in samples) if a pulse just ended
float duration = 1e6 * pulseLength / context->digitalSampleRate; // pulse duration in microseconds
static float distance = 0;
if(pulseLength >= gMinPulseLength){
static int count = 0;
// rescaling according to the datasheet
distance = duration / gRescale;
if(count > 5000){ // we do not want to print the value every time we read it
rt_printf("pulseLength: %d, distance: %fcm\n", pulseLength, distance);
count -= 5000;
}
++count;
}
// Logging to the scope the pulse inputs (gEchoDigitalInPin) and the distance
scope.log(digitalRead(context, n, gEchoDigitalInPin), distance/100);
}
}
void render(BelaContext *context, void *userData)
{
static bool pulseOut = 0;
static int count = 0;
for(unsigned int n = 0; n < context->digitalFrames; n++){
// detect if a pulse just ended
int duration = pulseIn.hasPulsed(context, n);
if(duration > 0){
rt_printf("duration = %d\n", duration);
}
// generate a rectangular waveform as a test signal.
// Connect gDigitalOutPin to gPulseInPin
// to verify that the detected pulse length is gPulseLength
if(count == gPulseLength ){
pulseOut = false;
}
if(count == (gPulseLength + gSamplesBetweenPulses)){
pulseOut = true;
count = 0;
}
digitalWrite(context, n, gDigitalOutPin, pulseOut);
count++;
}
}
bool setup(BelaContext *context, void *userData)
{
// Set the mode of digital pins
pinMode(context, 0, gEchoDigitalInPin, INPUT); // receiving from ECHO PIN
pulseIn.init(context, gEchoDigitalInPin, HIGH); //detect HIGH pulses on this pin
scope.setup(2, 44100);
if(context->analogInChannels != 8){
fprintf(stderr, "This project has to be run with 8 analog channels\n");
return false;
}
return true;
}
bool setup(BelaContext *context, void *userData)
{
pinMode(context, 0, gDigitalOutPin, OUTPUT);
pulseIn.init(context, gPulseInPin, 1); //third parameter is direction
return true;
}