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adc: no longer support adc2 oneshot mode on esp32c3

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Due to HW limitation, we don't support this anymore. On c3, ADC2 under oneshot mode is not stable.

However, you can enable CONFIG_ADC_ONESHOT_FORCE_USE_ADC2_ON_C3 to force use
ADC2.

Refer to errata to know more details:
https://www.espressif.com/sites/default/files/documentation/esp32-c3_errata_en.pdf
This commit is contained in:
Armando 2022-12-16 12:53:04 +08:00 committed by BOT
parent 9b4986dd2c
commit 984ee9dd38
4 changed files with 19 additions and 9 deletions
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11
components/driver/Kconfig
View File

@ -30,6 +30,17 @@ menu "Driver configurations"
If you stick to this, you can enable this option to force use ADC2 under above conditions.
For more details, you can search for errata on espressif website.
config ADC_ONESHOT_FORCE_USE_ADC2_ON_C3
depends on IDF_TARGET_ESP32C3
bool "Force use ADC2 oneshot mode on ESP32C3"
default n
help
On ESP32C3, ADC2 Digital Controller is not stable. Therefore,
ADC2 oneshot mode is not suggested on ESP32C3
If you stick to this, you can enable this option to force use ADC2 under above conditions.
For more details, you can search for errata on espressif website.
endmenu # ADC Configuration
menu "SPI configuration"

6
components/driver/esp32c3/adc.c
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@ -536,6 +536,12 @@ esp_err_t adc2_config_channel_atten(adc2_channel_t channel, adc_atten_t atten)
esp_err_t adc2_get_raw(adc2_channel_t channel, adc_bits_width_t width_bit, int *raw_out)
{
#if !CONFIG_ADC_ONESHOT_FORCE_USE_ADC2_ON_C3
ESP_LOGE(ADC_TAG, "ADC2 is no longer supported, please use ADC1. Search for errata on espressif website for more details. You can enable ADC_ONESHOT_FORCE_USE_ADC2_ON_C3 to force use ADC2");
ESP_LOGE(ADC_TAG, "adc unit not supported");
return ESP_ERR_INVALID_ARG;
#endif
//On ESP32C3, the data width is always 12-bits.
if (width_bit != ADC_WIDTH_BIT_12) {
return ESP_ERR_INVALID_ARG;

1
docs/en/api-reference/peripherals/adc.rst
View File

@ -60,6 +60,7 @@ ADC Limitations
- A specific ADC module can only work under one operating mode at any one time, either Continuous Read Mode or Single Read Mode.
- For continuous (DMA) read mode, the ADC sampling frequency (the ``sample_freq_hz`` member of :cpp:type:`adc_digi_config_t`) should be within ``SOC_ADC_SAMPLE_FREQ_THRES_LOW`` and ``SOC_ADC_SAMPLE_FREQ_THRES_HIGH``
- ADC2 continuous (DMA) mode is no longer supported, due to hardware limitation. The results are not stable. This issue can be found in `ESP32C3 Errata <https://www.espressif.com/sites/default/files/documentation/esp32-c3_errata_en.pdf>`. For compatibility, you can enable :ref:`CONFIG_ADC_CONTINUOUS_FORCE_USE_ADC2_ON_C3_S3` to force use ADC2.
- ADC2 oneshot mode is no longer supported, due to hardware limitation. The results are not stable. This issue can be found in `ESP32C3 Errata <https://www.espressif.com/sites/default/files/documentation/esp32-c3_errata_en.pdf>`. For compatibility, you can enable :ref:`CONFIG_ADC_ONESHOT_FORCE_USE_ADC2_ON_C3` to force use ADC2.
Driver Usage

10
examples/peripherals/adc/esp32c3/adc/main/adc_dma_example_main.c
View File

@ -87,17 +87,13 @@ static void continuous_read(void *arg)
static void single_read(void *arg)
{
esp_err_t ret;
int adc1_reading[3] = {0xcc};
int adc2_reading[1] = {0xcc};
const char TAG_CH[][10] = {"ADC1_CH2", "ADC1_CH3","ADC1_CH4", "ADC2_CH0"};
const char TAG_CH[][10] = {"ADC1_CH2", "ADC1_CH3","ADC1_CH4"};
adc1_config_width(ADC_WIDTH_BIT_DEFAULT);
adc1_config_channel_atten(ADC1_CHANNEL_2, ADC_ATTEN_DB_0);
adc1_config_channel_atten(ADC1_CHANNEL_3, ADC_ATTEN_DB_6);
adc1_config_channel_atten(ADC1_CHANNEL_4, ADC_ATTEN_DB_0);
adc2_config_channel_atten(ADC2_CHANNEL_0, ADC_ATTEN_DB_0);
int n = 20;
while (n--) {
@ -109,10 +105,6 @@ static void single_read(void *arg)
for (int i = 0; i < 3; i++) {
ESP_LOGI(TAG_CH[i], "%x", adc1_reading[i]);
}
ret = adc2_get_raw(ADC2_CHANNEL_0, ADC_WIDTH_BIT_12, &adc2_reading[0]);
assert(ret == ESP_OK);
ESP_LOGI(TAG_CH[3], "%x", adc2_reading[0]);
}
}