Slow ADC sampling

Meadow Development
1

I need to sample A0 hundreds of times a second.
I have simple code:

adc = Device.CreateAnalogInputPort( Device.Pins.A00 );
while ( true )
{
  var startacq = DateTime.Now.Ticks;
  var v = await adc.Read();
  var delta = DateTime.Now.Ticks - startacq;
  Console.WriteLine( $"delta={delta/10000} ms" );
}

This gives me a time of 237ms for the call to adc.Read();
I have confirmed this is the case with a logic analyser.

Why is the Read() function so slow?
Can it be speeded up?

Andy

2

The next release (RC-1) has Just-in-Time (JiT) compilation which has a magnitude or more speed up. We’re also talking about a way to re-jigger the AnalogInputPort to do continuous, fast-reads.

3

Bryan,

Thanks for the update - for industrial use, you definitely need the higher sampling rates.

Andy

4

Bryan, I have the same problem on an industrial device. 300ms on average at best:

      _analogIn = Device.CreateAnalogInputPort(Device.Pins.A00);
      _analogIn .StartUpdating(TimeSpan.FromMilliseconds(100));

Is there some hack to get around this and maybe just read raw voltage? Was .Read() ever updated? Thank you in advance for any help - this is very much a deal breaker, and I would love to keep using the Meadow F7v2 Feather.

And just to get the formalities out of the way: F7 was just bought, tested with several, updated to latest.

5

Following up on the above. I worked around this with bluetooth (which works very well), but would still like a hard-wired solution if possible.