No Sound :-(

[spinal]

@spinal

@spinal

Any I read for better speed?

? Does not compute

Fixed …

[MLXXXp]

@spinal

Any I ideas for better speed?

Write dedicated code to do it.

No Sound

It should. The black screen may be a flaw or limitation of whatever functions you’re using. Like I said previously, I’d try to do the whole thing under interrupts. Set a timer to trigger the ADC to acquire a reading every 20µs (50kHz). Set the ADC to generate an interrupt whenever an acquisition is complete. In the ADC interrupt service routine, read the ADC value, scale the reading (if necessary) and write it to the DAC0 output. The interrupt routine may also have to re-arm the ADC and/or do…

[jonne]

@MLXXXp

Write dedicated code to do it.

Seconded. The timer code of mbed library has a lot of overhead.

[spinal]

@MLXXXp

@MLXXXp

Write dedicated code to do it.

Seconded. The timer code of mbed library has a lot of overhead.

So something along the line of the way the audio playing timer is set up? of different?

[jonne]

The reason why the audio interrupt was made is because its about 5-10 times more efficient than using the default mbed interrupt

[spinal]

Hmmm, even overclocking isn’t helping much, I’ve read a few places that analogin is very slow. I’ll look at that tomorrow.

[MLXXXp]

@spinal

So something along the line of the way the audio playing timer is set up? of different?

As I’ve said, I wouldn’t use a timer interrupt for this. I would use a timer to generate a hardware trigger to start an ADC conversion. The ADC would be set to generate an interrupt when the triggered conversion was complete and its ISR would (perhaps condition and) echo the conversion result to the audio hardware.

If you use a timer interrupt to start the ADC, you then have to wait for the conversion to complete (which, because it takes a fair amount of time, you don’t want to do inside an interrupt service routine). This means you need to poll for conversion complete or still have an end of conversion interrupt.

You would set up the timer to run continuously such that it generates ADC hardware triggers at a rate of about 50kHz. This way, the echoing of the radio output to the audio hardware is done automatically “hands off” in the background while the regular foregroud code can do whatever it likes (like changing radio stations, adjusting the volume, etc.) without worrying about it.