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  • mborgerson's Avatar
    07-09-2021, 06:45 PM
    Your timing code will probably return 0 for all values in vImag; You could try something like this: void adc0_isr() { uint16_t adc_val; // call readSingle() to clear the interrupt. // and store the...
    22 replies | 656 view(s)
  • mborgerson's Avatar
    07-09-2021, 06:25 PM
    I ran my histogram analyzer that does 1,000,000 samples at 50uSec intervals for two cases: The first collects the ADC values for histogram analysis without SD card writes, the second collects the data and writes a...
    22 replies | 656 view(s)
  • mborgerson's Avatar
    07-07-2021, 09:59 PM
    If you simply called my GetADC function without change and captured the time before and after the call, the interval is going to be higher by 101 milliseconds due to the delay() calls in the function. If you left in...
    22 replies | 656 view(s)
  • mborgerson's Avatar
    07-07-2021, 03:49 AM
    With the OP's specification of 50uSec sampling, I think there is a low probability that the SysTick interrupt will affect the ADC timing. Both the ADC timer and the Systick timer are generated from the same system...
    22 replies | 656 view(s)
  • mborgerson's Avatar
    07-06-2021, 06:55 PM
    Here is a simple demo program to collect 16384 samples using the ADC timer. // Sample program to Collect ADC data with ADC timer // Using the ADC timer to collect minimizes sampling jitter // Targeted to T4.0 at...
    22 replies | 656 view(s)
  • mborgerson's Avatar
    07-06-2021, 02:00 PM
    I've got lots of example code that might be applicable, but your question is a bit too vague. To pull out the right example I need to know: 1. Which Teensy are you using? 2. How many samples do you need to...
    22 replies | 656 view(s)
  • mborgerson's Avatar
    07-05-2021, 10:17 PM
    Another possibility is to use the ADC library and the hardware ADC timer. It is also more complex in that you have to know how to set up and use an interrupt to collect the data-- but it gets you jitter-free sampling.
    22 replies | 656 view(s)
  • mborgerson's Avatar
    06-07-2021, 02:45 AM
    Perhaps the lower input voltage results in a slower V_3.3 rise time and the 1.5K pull-up resistor used to pull up the USB DP signal isn't pulling up quickly enough and the PC is lacking the signal needed to start...
    9 replies | 373 view(s)
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About mborgerson

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About mborgerson
Biography:
building embedded systems for oceanographers since 1978
Location:
Corvallis, OR
Interests:
travel
Occupation:
Retired embedded systems engineer

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analogRead sampling 07-09-2021 06:45 PM
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02-01-2018