What means ADC0_RA

[Oleum]

I understand it to be an indication of the ADC.

But with my Teensy 4.1 I get the message that:
'ADC0_RA' was not declared in this scope; did you mean 'ADC1_R6'.
I want to use pin A8.
Where does the result for A8 come from in this function?

Could someone please explain this function to me?

/* the function uint16_t analogReadFastADC0(uint8_t pin)
 * is from ADC.cpp and ADC_Module.cpp, here specialised for ADC0 
 * for more speed; this one takes 2,2 us with f_CPU = 96 MHz
 */
uint16_t analogReadFastADC0(uint8_t pin){
  uint16_t result;
  
  adc->adc0->startReadFast(pin);      // start single read (with adc->adc0->singleMode(); in setup() )
  while(adc->adc0->isConverting()) {} // wait for the ADC to finish
                                      //  __disable_irq();
  result = (uint16_t)[B]ADC0_RA;[/B]
                                      //   __enable_irq();
  return result;
}

 

[el_supremo]

The comment in the code about "f_CPU = 96 MHz" suggests that it was written for the Teensy 3.x series.
The T4.1 probably doesn't have a ADC0_RA register.

Pete

 

[Oleum]

Thank you for the clarification.
And how can I translate this information into Teensy 4.1?

 

[PaulStoffregen]

And how can I translate this information into Teensy 4.1?

Did you try this first?

uint16_t analogReadFastADC0(uint8_t pin) {
  return analogRead(pin);
}

If this very simple way is good enough, why make things more complicated than they need to be?

 

[Oleum]

If this very simple way is good enough, why make things more complicated than they need to be?

Because I tried this:
https://forum.pjrc.com/threads/52569-TCD1304-with-teensy-3-2

He had tried to use the fastest way to read out the ADC

As you have already read in my question:
https://forum.pjrc.com/threads/73676-USB-Timer-AnalogRead-Interrupt
I get strange effects when I use my program described there.
That's why I wanted to see if I can test an even faster method for the ADC.
But maybe USB, interrupt and ADC interfere with each other