example(adc2): add example and test case for adc2.

closes #461

components/driver/test/test_adc2.c

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+/*
+ Tests for the adc2 device driver
+*/
+#include "esp_system.h"
+#include "driver/adc.h"
+#include "driver/dac.h"
+#include "unity.h"
+#include "esp_system.h"
+#include "esp_event_loop.h"
+#include "esp_wifi.h"
+#include "esp_log.h"
+#include "nvs_flash.h"
+
+static const char* TAG = "test_adc2";
+
+#define DEFAULT_SSID "TEST_SSID"
+#define DEFAULT_PWD "TEST_PASS"
+
+static esp_err_t event_handler(void *ctx, system_event_t *event)
+{
+    printf("ev_handle_called.\n");
+    switch(event->event_id) {
+        case SYSTEM_EVENT_STA_START:
+            ESP_LOGI(TAG, "SYSTEM_EVENT_STA_START");
+    //do not actually connect in test case
+            //;
+            break;
+        case SYSTEM_EVENT_STA_GOT_IP:
+            ESP_LOGI(TAG, "SYSTEM_EVENT_STA_GOT_IP");
+            ESP_LOGI(TAG, "got ip:%s\n",
+            ip4addr_ntoa(&event->event_info.got_ip.ip_info.ip));
+            break;
+        case SYSTEM_EVENT_STA_DISCONNECTED:
+            ESP_LOGI(TAG, "SYSTEM_EVENT_STA_DISCONNECTED");
+            TEST_ESP_OK(esp_wifi_connect());
+            break;
+        default:
+            break;
+    }
+    return ESP_OK;
+}
+
+TEST_CASE("adc2 work with wifi","[adc]")
+{
+    int     read_raw;
+    int     target_value;
+    
+    //adc and dac init
+    TEST_ESP_OK( dac_output_enable( DAC_CHANNEL_1 ));
+    TEST_ESP_OK( dac_output_enable( DAC_CHANNEL_2 ));
+    TEST_ESP_OK( dac_output_voltage( DAC_CHANNEL_1, 30 ));
+    TEST_ESP_OK( dac_output_voltage( DAC_CHANNEL_2, 60 ));
+    TEST_ESP_OK( adc2_config_channel_atten( ADC2_CHANNEL_8, ADC_ATTEN_0db ));
+    TEST_ESP_OK( adc2_config_channel_atten( ADC2_CHANNEL_9, ADC_ATTEN_0db ));
+
+    //init wifi
+    printf("nvs init\n");
+    esp_err_t r = nvs_flash_init();
+    if (r == ESP_ERR_NVS_NO_FREE_PAGES) {
+        printf("no free pages, erase..\n");
+        TEST_ESP_OK(nvs_flash_erase());
+        r = nvs_flash_init();
+    } 
+    TEST_ESP_OK( r);
+    tcpip_adapter_init();
+    TEST_ESP_OK(esp_event_loop_init(event_handler, NULL));
+    wifi_init_config_t cfg = WIFI_INIT_CONFIG_DEFAULT();
+    TEST_ESP_OK(esp_wifi_init(&cfg));
+    wifi_config_t wifi_config = {
+        .sta = {
+            .ssid = DEFAULT_SSID,
+            .password = DEFAULT_PWD
+        },
+    };
+    TEST_ESP_OK(esp_wifi_set_mode(WIFI_MODE_STA));
+    TEST_ESP_OK(esp_wifi_set_config(ESP_IF_WIFI_STA, &wifi_config));
+    
+    //test read value
+    TEST_ESP_OK( adc2_get_raw( ADC2_CHANNEL_8, ADC_WIDTH_12Bit, &read_raw ));
+    target_value = 30*4096*3/256; //3 = 3.3/1.1
+    printf("dac set: %d, adc read: %d (target_value: %d)\n", 30, read_raw, target_value );
+    TEST_ASSERT_INT_WITHIN( 600, target_value, read_raw );
+    TEST_ESP_OK( adc2_get_raw( ADC2_CHANNEL_9, ADC_WIDTH_12Bit, &read_raw ));
+    target_value = 60*4096*3/256;
+    printf("dac set: %d, adc read: %d (target_value: %d)\n", 60, read_raw, target_value );
+    TEST_ASSERT_INT_WITHIN( 600, target_value, read_raw );
+
+    //now start wifi
+    printf("wifi start...\n");
+    TEST_ESP_OK(esp_wifi_start());
+
+    //test reading during wifi on
+    TEST_ASSERT_EQUAL( adc2_get_raw( ADC2_CHANNEL_8, ADC_WIDTH_12Bit, &read_raw ), ESP_ERR_TIMEOUT );
+    TEST_ASSERT_EQUAL( adc2_get_raw( ADC2_CHANNEL_9, ADC_WIDTH_12Bit, &read_raw ), ESP_ERR_TIMEOUT );
+
+    //wifi stop again
+    printf("wifi stop...\n");
+    TEST_ESP_OK( esp_wifi_stop() );
+    TEST_ESP_OK(esp_wifi_deinit());
+    nvs_flash_deinit();
+
+    //test read value
+    TEST_ESP_OK( adc2_get_raw( ADC2_CHANNEL_8, ADC_WIDTH_12Bit, &read_raw ));
+    target_value = 30*4096*3/256; //3 = 3.3/1.1
+    printf("dac set: %d, adc read: %d (target_value: %d)\n", 30, read_raw, target_value );
+    TEST_ASSERT_INT_WITHIN( 600, target_value, read_raw );
+    TEST_ESP_OK( adc2_get_raw( ADC2_CHANNEL_9, ADC_WIDTH_12Bit, &read_raw ));
+    target_value = 60*4096*3/256;
+    printf("dac set: %d, adc read: %d (target_value: %d)\n", 60, read_raw, target_value );
+    TEST_ASSERT_INT_WITHIN( 600, target_value, read_raw );
+
+    printf("test passed...\n");
+
+    TEST_IGNORE_MESSAGE("this test case is ignored due to the critical memory leak of tcpip_adapter and event_loop.");
+}

examples/peripherals/adc2/Makefile

@@ -0,0 +1,9 @@
+#
+# 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/adc2/README.md

@@ -0,0 +1,29 @@
+# Example: ADC2
+
+This test code shows how to configure ADC2 and read the voltage connected to GPIO pin.
+
+ 
+### ADC2 functions:
+
+ADC1_CHANNEL_7: GPIO27, voltage range [0V..3.1V], the data range [0..4095],
+saturates at about 1.1V.
+
+DAC_CHANNEL_1: GPIO25, output range [0V..3.3V]
+
+ 
+### Test:
+
+Please choose the channel (GPIO) to output DAC signals and the channel to input 
+signals to ADC by menuconfig:
+    
+    make menuconfig
+
+Then connect two pins by a wire directly. 
+
+E.g. Choose GPIO27 for ADC and GPIO 25 for DAC in menuconfig (default option).
+Then connect them up.
+
+Connection of ADC and DAC to the same pin is also allowed. In this case, you don't
+have to connect by a wire externally. E.g. choose GPIO 26 for both ADC and DAC in
+menuconfig.
+

examples/peripherals/adc2/main/Kconfig.projbuild

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+menu "Example Configuration"
+
+choice ADC2_EXAMPLE_CHANNEL
+    bool "ADC2 Channel Num"
+    default ADC2_EXAMPLE_CHANNEL_7
+    help
+        The channel of ADC2 used in this example.
+
+config ADC2_EXAMPLE_CHANNEL_0
+   bool "ADC2 Channel 0 (GPIO 4)"
+config ADC2_EXAMPLE_CHANNEL_1
+   bool "ADC2 Channel 1 (GPIO 0)"
+config ADC2_EXAMPLE_CHANNEL_2
+   bool "ADC2 Channel 2 (GPIO 2)"
+config ADC2_EXAMPLE_CHANNEL_3
+   bool "ADC2 Channel 3 (GPIO 15)"
+config ADC2_EXAMPLE_CHANNEL_4
+   bool "ADC2 Channel 4 (GPIO 13)"
+config ADC2_EXAMPLE_CHANNEL_5
+   bool "ADC2 Channel 5 (GPIO 12)"
+config ADC2_EXAMPLE_CHANNEL_6
+   bool "ADC2 Channel 6 (GPIO 14)"
+config ADC2_EXAMPLE_CHANNEL_7
+   bool "ADC2 Channel 7 (GPIO 27)"
+config ADC2_EXAMPLE_CHANNEL_8
+   bool "ADC2 Channel 8 (GPIO 25)"
+config ADC2_EXAMPLE_CHANNEL_9
+   bool "ADC2 Channel 9 (GPIO 26)"
+endchoice
+
+config ADC2_EXAMPLE_CHANNEL
+    int 
+    default 0 if ADC2_EXAMPLE_CHANNEL_0
+    default 1 if ADC2_EXAMPLE_CHANNEL_1
+    default 2 if ADC2_EXAMPLE_CHANNEL_2
+    default 3 if ADC2_EXAMPLE_CHANNEL_3
+    default 4 if ADC2_EXAMPLE_CHANNEL_4
+    default 5 if ADC2_EXAMPLE_CHANNEL_5
+    default 6 if ADC2_EXAMPLE_CHANNEL_6
+    default 7 if ADC2_EXAMPLE_CHANNEL_7
+    default 8 if ADC2_EXAMPLE_CHANNEL_8
+    default 9 if ADC2_EXAMPLE_CHANNEL_9
+
+choice DAC_EXAMPLE_CHANNEL
+    bool "DAC Channel Num"
+    default DAC_EXAMPLE_CHANNEL_1
+    help
+        The channel of DAC used in this example.
+
+config DAC_EXAMPLE_CHANNEL_1
+   bool "DAC Channel 1 (GPIO25)"
+config DAC_EXAMPLE_CHANNEL_2
+   bool "DAC Channel 2 (GPIO26)"
+endchoice
+
+config DAC_EXAMPLE_CHANNEL
+    int 
+    default 1 if DAC_EXAMPLE_CHANNEL_1
+    default 2 if DAC_EXAMPLE_CHANNEL_2
+
+endmenu

examples/peripherals/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"
+#include "esp_adc_cal.h"
+
+#define DAC_EXAMPLE_CHANNEL     CONFIG_DAC_EXAMPLE_CHANNEL
+#define ADC2_EXAMPLE_CHANNEL    CONFIG_ADC2_EXAMPLE_CHANNEL
+
+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;
+
+    assert( adc2_pad_get_io_num( ADC2_EXAMPLE_CHANNEL, &adc_gpio_num ) == ESP_OK );
+    assert( dac_pad_get_io_num( DAC_EXAMPLE_CHANNEL, &dac_gpio_num ) == ESP_OK );
+
+    printf("ADC channel %d @ GPIO %d, DAC channel %d @ GPIO %d.\n", ADC2_EXAMPLE_CHANNEL, adc_gpio_num,
+                DAC_EXAMPLE_CHANNEL, 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_0db );
+
+    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, ADC_WIDTH_12Bit, &read_raw);
+        if ( r == ESP_OK ) {
+            printf("%d: %d\n", output_data, read_raw );
+        } else if ( r == ESP_ERR_INVALID_STATE ) {
+            printf("ADC2 not initialized yet.\n");
+        } 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("ADC2 is in use by Wi-Fi.\n");
+        }
+        vTaskDelay( 2 * portTICK_PERIOD_MS );
+    }
+}

examples/peripherals/adc2/main/component.mk

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