dec4a868d0
Also increase sampling frequency in ulp_adc example and update READMEs. Fixes https://github.com/espressif/esp-idf/issues/1108
45 lines
1.2 KiB
Markdown
45 lines
1.2 KiB
Markdown
# ULP ADC Example
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This example demonstrates how to use the ULP coprocessor to poll ADC in deep sleep.
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ULP program periodically measures the input voltage on GPIO34. The voltage is compared to two thresholds. If the voltage is less than the low threshold, or higher than the high threshold, ULP wakes up the system.
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By default, thresholds are set to 1.35V and 1.75V, approximately.
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GPIO15 is connected to ground to supress output from ROM bootloader.
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Average current drawn by the ESP32 in this example (with the default 4x averaging) depending on the measurement frequency is as follows:
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Measurement frequency, Hz | Average current, uA
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--------------------------|---------------------
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10 | 8.5
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50 | 20
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100 | 37
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## Example output
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Below is the output from this example.
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```
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Not ULP wakeup
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Entering deep sleep
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Deep sleep wakeup
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ULP did 1531 measurements
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Thresholds: low=1500 high=2000
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Value=973 was below threshold
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Entering deep sleep
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Deep sleep wakeup
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ULP did 2 measurements
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Thresholds: low=1500 high=2000
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Value=0 was below threshold
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Entering deep sleep
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Deep sleep wakeup
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ULP did 2 measurements
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Thresholds: low=1500 high=2000
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Value=0 was below threshold
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Entering deep sleep
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```
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