test_io.c

#include <stdio.h>
#include <unistd.h>
#include "driver/adc.h"
#include "driver/gpio.h"
#include "driver/rtc_io.h"
#include "soc/cpu.h"

const char* names[] = {"D2", "D3", "CLK", "CMD", "D0", "D1"};
const int pins[] = {12, 13, 14, 15, 2, 4};
const int adc_channels[] = {5, 4, 6, 3, 2, 0};
const int pin_count = sizeof(pins)/sizeof(pins[0]);
const int adc_sample_count = 100;
const float adc_fs_v = 3.3f;

static float get_pin_voltage(int i) {
    ESP_ERROR_CHECK(adc2_config_channel_atten(adc_channels[i], ADC_ATTEN_DB_11));
    int avg_val = 0;
    for (int sample = 0; sample < adc_sample_count; ++sample) {
        int val;
        ESP_ERROR_CHECK(adc2_get_raw(adc_channels[i], ADC_WIDTH_BIT_10, &val));
        avg_val += val;
    }
    avg_val = (avg_val + adc_sample_count / 2) / adc_sample_count;
    return avg_val * adc_fs_v / 1024;
}

static uint32_t get_cycles_until_pin_level(int i, int level, int timeout) {
    uint32_t start = esp_cpu_get_ccount();
    while(rtc_gpio_get_level(pins[i]) == !level && esp_cpu_get_ccount() - start < timeout) {
        ;
    }
    uint32_t end = esp_cpu_get_ccount();
    return end - start;
}

void check_sd_card_pins(void)
{

    printf("\nSD Card I/O check. Make sure the SD card is NOT plugged in!\n");

    for (int i = 0; i < pin_count; ++i) {
        rtc_gpio_init(pins[i]);
        rtc_gpio_set_direction(pins[i], RTC_GPIO_MODE_INPUT_ONLY);
        rtc_gpio_pullup_dis(pins[i]);
        rtc_gpio_pulldown_dis(pins[i]);
    }

    printf("\n\t**** Checking idle levels ****\n\n");

    for (int i = 0; i < pin_count; ++i) {
        float voltage = get_pin_voltage(i);
        printf("PIN %2d %3s  %.1fV\n", pins[i], names[i], voltage);
    }

    printf("\n\t**** Checking levels with weak pullup ****\n\n");

    for (int i = 0; i < pin_count; ++i) {
        rtc_gpio_pullup_en(pins[i]);
        usleep(100);
        float voltage = get_pin_voltage(i);
        printf("PIN %2d %3s  %.1fV\n", pins[i], names[i], voltage);
        rtc_gpio_pullup_dis(pins[i]);
    }

    printf("\n\t**** Checking pin recovery time ****\n\n");

    for (int i = 0; i < pin_count; ++i) {
        rtc_gpio_set_direction(pins[i], RTC_GPIO_MODE_INPUT_OUTPUT_OD);
        rtc_gpio_set_level(pins[i], 0);
        usleep(100);
        rtc_gpio_set_level(pins[i], 1);
        uint32_t cycles = get_cycles_until_pin_level(i, 1, 10000);
        printf("PIN %2d %3s  %u cycles\n", pins[i], names[i], cycles);
        rtc_gpio_set_direction(pins[i], RTC_GPIO_MODE_INPUT_ONLY);
    }

    printf("\n\t**** Checking pin recovery time with weak pullup ****\n\n");

    for (int i = 0; i < pin_count; ++i) {
        rtc_gpio_set_direction(pins[i], RTC_GPIO_MODE_INPUT_OUTPUT_OD);
        rtc_gpio_pullup_en(pins[i]);
        rtc_gpio_set_level(pins[i], 0);
        usleep(100);
        rtc_gpio_set_level(pins[i], 1);
        uint32_t cycles = get_cycles_until_pin_level(i, 1, 10000);
        printf("PIN %2d %3s  %u cycles\n", pins[i], names[i], cycles);
        rtc_gpio_pullup_dis(pins[i]);
        rtc_gpio_set_direction(pins[i], RTC_GPIO_MODE_INPUT_ONLY);
    }

    printf("\n\t**** Checking pin cross-talk ****\n\n");

    printf("              ");
    for (int i = 0; i < pin_count; ++i) {
        printf("%3s   ", names[i]);
    }
    printf("\n");
    for (int i = 0; i < pin_count; ++i) {
        rtc_gpio_set_direction(pins[i], RTC_GPIO_MODE_INPUT_OUTPUT_OD);
        rtc_gpio_set_level(pins[i], 0);
        printf("PIN %2d %3s    ", pins[i], names[i]);
        for (int j = 0; j < pin_count; ++j) {
            if (j == i) {
                printf(" --   ");
                continue;
            }
            usleep(100);
            float voltage = get_pin_voltage(j);
            printf("%1.1fV  ", voltage);
        }
        printf("\n");
        rtc_gpio_set_direction(pins[i], RTC_GPIO_MODE_INPUT_ONLY);
    }

    printf("\n\t**** Checking pin cross-talk with weak pull-up ****\n\n");

    printf("              ");
    for (int i = 0; i < pin_count; ++i) {
        printf("%3s   ", names[i]);
    }
    printf("\n");
    for (int i = 0; i < pin_count; ++i) {
        rtc_gpio_set_direction(pins[i], RTC_GPIO_MODE_INPUT_OUTPUT_OD);
        rtc_gpio_set_level(pins[i], 0);
        printf("PIN %2d %3s    ", pins[i], names[i]);
        for (int j = 0; j < pin_count; ++j) {
            if (j == i) {
                printf(" --   ");
                continue;
            }
            rtc_gpio_pullup_en(pins[j]);
            usleep(100);
            float voltage = get_pin_voltage(j);
            printf("%1.1fV  ", voltage);
            rtc_gpio_pullup_dis(pins[j]);
        }
        printf("\n");
        rtc_gpio_set_direction(pins[i], RTC_GPIO_MODE_INPUT_ONLY);
    }

}