ADC Module¶
Since | Origin / Contributor | Maintainer | Source |
---|---|---|---|
2017-04-22 | zelll | zelll | adc.c |
The ADC module provides access to the in-built ADC1.
On the ESP32 there are two ADC. ADC1 has 8 channels, while ADC2 has 10 channels. Currently, only ADC1 is supported.
adc.setwidth()¶
The configuration is in effect for all channels of ADC1
Syntax¶
adc.setwidth(adc_number, bits)
Parameters¶
adc_number
Onlyadc.ADC1
nowbits
One of9
/10
/11
/12
.
Returns¶
nil
adc.setup()¶
Configuration ADC1 capture attenuation of channels
Syntax¶
adc.setup(adc_number, channel, atten)
Parameters¶
adc_number
Onlyadc.ADC1
nowchannel
When usingadc.ADC1
:0
to7
. 0: GPIO36, 1: GPIO37, 2: GPIO38, 3: GPIO39, 4: GPIO32, 5: GPIO33, 6: GPIO34, 7: GPIO35atten
One of following constantsadc.ATTEN_0db
The input voltage of ADC will be reduced to about 1/1 (1.1V when VDD_A=3.3V)adc.ATTEN_2_5db
The input voltage of ADC will be reduced to about 1/1.34 (1.5V when VDD_A=3.3V)adc.ATTEN_6db
The input voltage of ADC will be reduced to about 1/2 (2.2V when VDD_A=3.3V)adc.ATTEN_11db
The input voltage of ADC will be reduced to about 1/3.6 (3.9V when VDD_A=3.3V, maximum voltage is limited by VDD_A)
Returns¶
nil
adc.read()¶
Samples the ADC. You should to call setwidth()
before read()
.
Syntax¶
adc.read(adc_number, channel)
Parameters¶
adc_number
Onlyadc.ADC1
nowchannel
0 to 7 for adc.ADC1
Returns¶
the sampled value (number)
Example¶
val = adc.read(adc.ADC1, 0)