adc: rename adc examples according to hw feature and usage

examples/peripherals/adc/single_read/adc2/CMakeLists.txt

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+# The following lines of boilerplate have to be in your project's CMakeLists
+# in this exact order for cmake to work correctly
+cmake_minimum_required(VERSION 3.5)
+
+include($ENV{IDF_PATH}/tools/cmake/project.cmake)
+project(adc2)

examples/peripherals/adc/single_read/adc2/Makefile

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+#
+# This is a project Makefile. It is assumed the directory this Makefile resides in is a
+# project subdirectory.
+#
+
+PROJECT_NAME := adc2
+
+include $(IDF_PATH)/make/project.mk

examples/peripherals/adc/single_read/adc2/README.md

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+| Supported Targets | ESP32 |
+| ----------------- | ----- |
+
+# ADC2 Example
+
+(See the README.md file in the upper level 'examples' directory for more information about examples.)
+
+In this example, we use ADC2 to measure the output of DAC.
+
+## How to use example
+
+### Hardware Required
+
+#### ESP32 platform
+
+* A development board with ESP32 SoC (e.g., ESP32-DevKitC, ESP-WROVER-KIT, etc.)
+* A USB cable for power supply and programming
+
+We use ADC1_CHANNEL_7 (GPIO27) and DAC_CHANNEL_1 (GPIO25) by default, you need to short the two GPIOs (if you have changed the ADC2 and DAC channel, please refer to Chapter 4.11 of the `ESP32 Technical Reference Manual` to get the pin number).
+
+#### ESP32-S2 platform
+
+* A development board with ESP32S2 SoC
+* A USB cable for power supply and programming
+
+We use ADC1_CHANNEL_7 (GPIO18) and DAC_CHANNEL_1 (GPIO17) by default, you need to short the two GPIOs (if you have changed the ADC2 and DAC channel, please refer to the `ESP32S2 Technical Reference Manual` to get the pin number).
+
+### Configure the project
+
+```
+idf.py menuconfig
+```
+* Set ADC2 and DAC channel in "Example Configuration"
+
+### Build and Flash
+
+Build the project and flash it to the board, then run monitor tool to view serial output:
+
+```
+idf.py -p PORT flash monitor
+```
+
+(To exit the serial monitor, type ``Ctrl-]``.)
+
+See the Getting Started Guide for full steps to configure and use ESP-IDF to build projects.
+
+## Example Output
+
+Running this example, you will see the following log output on the serial monitor:
+
+### ESP32 platform
+
+```
+ADC channel 7 @ GPIO 27, DAC channel 1 @ GPIO 25.
+adc2_init...
+start conversion.
+1: 150
+2: 203
+3: 250
+4: 300
+5: 351
+6: 400
+7: 441
+8: 491
+9: 547
+10: 595
+...
+```
+
+#### ESP32-S2 platform
+
+```
+ADC channel 7 @ GPIO 18, DAC channel 1 @ GPIO 17.
+adc2_init...
+start conversion.
+1: 150
+2: 203
+3: 250
+4: 300
+5: 351
+6: 400
+7: 441
+8: 491
+9: 547
+10: 595
+...
+```
+
+## Troubleshooting
+
+* program upload failure
+
+    * Hardware connection is not correct: run `idf.py -p PORT monitor`, and reboot your board to see if there are any output logs.
+    * The baud rate for downloading is too high: lower your baud rate in the `menuconfig` menu, and try again.
+
+For any technical queries, please open an [issue](https://github.com/espressif/esp-idf/issues) on GitHub. We will get back to you soon.

examples/peripherals/adc/single_read/adc2/main/CMakeLists.txt

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+idf_component_register(SRCS "adc2_example_main.c"
+                    INCLUDE_DIRS ".")

examples/peripherals/adc/single_read/adc2/main/Kconfig.projbuild

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+menu "Example Configuration"
+
+    choice EXAMPLE_ADC2_CHANNEL
+        bool "ADC2 Channel Num"
+        depends on IDF_TARGET_ESP32
+        default EXAMPLE_ADC2_CHANNEL_7
+        help
+            The channel of ADC2 used in this example.
+
+        config EXAMPLE_ADC2_CHANNEL_0
+            bool "ADC2 Channel 0 (GPIO 4)"
+        config EXAMPLE_ADC2_CHANNEL_1
+            bool "ADC2 Channel 1 (GPIO 0)"
+        config EXAMPLE_ADC2_CHANNEL_2
+            bool "ADC2 Channel 2 (GPIO 2)"
+        config EXAMPLE_ADC2_CHANNEL_3
+            bool "ADC2 Channel 3 (GPIO 15)"
+        config EXAMPLE_ADC2_CHANNEL_4
+            bool "ADC2 Channel 4 (GPIO 13)"
+        config EXAMPLE_ADC2_CHANNEL_5
+            bool "ADC2 Channel 5 (GPIO 12)"
+        config EXAMPLE_ADC2_CHANNEL_6
+            bool "ADC2 Channel 6 (GPIO 14)"
+        config EXAMPLE_ADC2_CHANNEL_7
+            bool "ADC2 Channel 7 (GPIO 27)"
+        config EXAMPLE_ADC2_CHANNEL_8
+            bool "ADC2 Channel 8 (GPIO 25)"
+        config EXAMPLE_ADC2_CHANNEL_9
+            bool "ADC2 Channel 9 (GPIO 26)"
+    endchoice
+
+    choice EXAMPLE_ADC2_CHANNEL
+        bool "ADC2 Channel Num"
+        depends on IDF_TARGET_ESP32S2
+        default EXAMPLE_ADC2_CHANNEL_7
+        help
+            The channel of ADC2 used in this example.
+
+        config EXAMPLE_ADC2_CHANNEL_0
+            bool "ADC2 Channel 0 (GPIO 11)"
+        config EXAMPLE_ADC2_CHANNEL_1
+            bool "ADC2 Channel 1 (GPIO 12)"
+        config EXAMPLE_ADC2_CHANNEL_2
+            bool "ADC2 Channel 2 (GPIO 13)"
+        config EXAMPLE_ADC2_CHANNEL_3
+            bool "ADC2 Channel 3 (GPIO 14)"
+        config EXAMPLE_ADC2_CHANNEL_4
+            bool "ADC2 Channel 4 (GPIO 15)"
+        config EXAMPLE_ADC2_CHANNEL_5
+            bool "ADC2 Channel 5 (GPIO 16)"
+        config EXAMPLE_ADC2_CHANNEL_6
+            bool "ADC2 Channel 6 (GPIO 17)"
+        config EXAMPLE_ADC2_CHANNEL_7
+            bool "ADC2 Channel 7 (GPIO 18)"
+        config EXAMPLE_ADC2_CHANNEL_8
+            bool "ADC2 Channel 8 (GPIO 19)"
+        config EXAMPLE_ADC2_CHANNEL_9
+            bool "ADC2 Channel 9 (GPIO 20)"
+    endchoice
+
+    config EXAMPLE_ADC2_CHANNEL
+        int
+        default 0 if EXAMPLE_ADC2_CHANNEL_0
+        default 1 if EXAMPLE_ADC2_CHANNEL_1
+        default 2 if EXAMPLE_ADC2_CHANNEL_2
+        default 3 if EXAMPLE_ADC2_CHANNEL_3
+        default 4 if EXAMPLE_ADC2_CHANNEL_4
+        default 5 if EXAMPLE_ADC2_CHANNEL_5
+        default 6 if EXAMPLE_ADC2_CHANNEL_6
+        default 7 if EXAMPLE_ADC2_CHANNEL_7
+        default 8 if EXAMPLE_ADC2_CHANNEL_8
+        default 9 if EXAMPLE_ADC2_CHANNEL_9
+
+    choice EXAMPLE_DAC_CHANNEL
+        bool "DAC Channel Num"
+        depends on IDF_TARGET_ESP32
+        default EXAMPLE_DAC_CHANNEL_1
+        help
+            The channel of DAC used in this example.
+
+        config EXAMPLE_DAC_CHANNEL_1
+            bool "DAC Channel 1 (GPIO25)"
+        config EXAMPLE_DAC_CHANNEL_2
+            bool "DAC Channel 2 (GPIO26)"
+    endchoice
+
+    choice EXAMPLE_DAC_CHANNEL
+        bool "DAC Channel Num"
+        depends on IDF_TARGET_ESP32S2
+        default EXAMPLE_DAC_CHANNEL_1
+        help
+            The channel of DAC used in this example.
+
+        config EXAMPLE_DAC_CHANNEL_1
+            bool "DAC Channel 1 (GPIO17)"
+        config EXAMPLE_DAC_CHANNEL_2
+            bool "DAC Channel 2 (GPIO18)"
+    endchoice
+
+    config EXAMPLE_DAC_CHANNEL
+        int
+        default 0 if EXAMPLE_DAC_CHANNEL_1
+        default 1 if EXAMPLE_DAC_CHANNEL_2
+
+endmenu

examples/peripherals/adc/single_read/adc2/main/adc2_example_main.c

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+/* ADC2 Example
+
+   This example code is in the Public Domain (or CC0 licensed, at your option.)
+
+   Unless required by applicable law or agreed to in writing, this
+   software is distributed on an "AS IS" BASIS, WITHOUT WARRANTIES OR
+   CONDITIONS OF ANY KIND, either express or implied.
+*/
+#include <stdio.h>
+#include <stdlib.h>
+#include "freertos/FreeRTOS.h"
+#include "freertos/task.h"
+#include "freertos/queue.h"
+#include "driver/gpio.h"
+#include "driver/adc.h"
+#include "driver/dac.h"
+#include "esp_system.h"
+
+#define DAC_EXAMPLE_CHANNEL     CONFIG_EXAMPLE_DAC_CHANNEL
+#define ADC2_EXAMPLE_CHANNEL    CONFIG_EXAMPLE_ADC2_CHANNEL
+
+#if CONFIG_IDF_TARGET_ESP32
+static const adc_bits_width_t width = ADC_WIDTH_BIT_12;
+#elif CONFIG_IDF_TARGET_ESP32S2
+static const adc_bits_width_t width = ADC_WIDTH_BIT_13;
+#endif
+
+void app_main(void)
+{
+    uint8_t output_data=0;
+    int     read_raw;
+    esp_err_t r;
+
+    gpio_num_t adc_gpio_num, dac_gpio_num;
+
+    r = adc2_pad_get_io_num( ADC2_EXAMPLE_CHANNEL, &adc_gpio_num );
+    assert( r == ESP_OK );
+    r = dac_pad_get_io_num( DAC_EXAMPLE_CHANNEL, &dac_gpio_num );
+    assert( r == ESP_OK );
+
+    printf("ADC2 channel %d @ GPIO %d, DAC channel %d @ GPIO %d.\n", ADC2_EXAMPLE_CHANNEL, adc_gpio_num,
+                DAC_EXAMPLE_CHANNEL + 1, dac_gpio_num );
+
+    dac_output_enable( DAC_EXAMPLE_CHANNEL );
+
+    //be sure to do the init before using adc2.
+    printf("adc2_init...\n");
+    adc2_config_channel_atten( ADC2_EXAMPLE_CHANNEL, ADC_ATTEN_11db );
+
+    vTaskDelay(2 * portTICK_PERIOD_MS);
+
+    printf("start conversion.\n");
+    while(1) {
+        dac_output_voltage( DAC_EXAMPLE_CHANNEL, output_data++ );
+        r = adc2_get_raw( ADC2_EXAMPLE_CHANNEL, width, &read_raw);
+        if ( r == ESP_OK ) {
+            printf("%d: %d\n", output_data, read_raw );
+        } else if ( r == ESP_ERR_INVALID_STATE ) {
+            printf("%s: ADC2 not initialized yet.\n", esp_err_to_name(r));
+        } else if ( r == ESP_ERR_TIMEOUT ) {
+            //This can not happen in this example. But if WiFi is in use, such error code could be returned.
+            printf("%s: ADC2 is in use by Wi-Fi.\n", esp_err_to_name(r));
+        } else {
+            printf("%s\n", esp_err_to_name(r));
+        }
+
+        vTaskDelay( 2 * portTICK_PERIOD_MS );
+    }
+}

examples/peripherals/adc/single_read/adc2/main/component.mk

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+#
+# Main Makefile. This is basically the same as a component makefile.
+#