Some development boards do not have sufficient external pull-ups on SD card pins. Most notably, if high level on GPIO13 is not registered by the card when GO_IDLE_STATE command is received, the card will enter SPI mode and further communication will not be possible, until power to the card is toggled. This change enables internal pull-ups on SD card pins in an attempt to make this initialization process more reliable.
154 lines
5.4 KiB
C
154 lines
5.4 KiB
C
/* SD card and FAT filesystem example.
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This example code is in the Public Domain (or CC0 licensed, at your option.)
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Unless required by applicable law or agreed to in writing, this
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software is distributed on an "AS IS" BASIS, WITHOUT WARRANTIES OR
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CONDITIONS OF ANY KIND, either express or implied.
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*/
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#include <stdio.h>
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#include <string.h>
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#include <sys/unistd.h>
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#include <sys/stat.h>
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#include "esp_err.h"
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#include "esp_log.h"
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#include "esp_vfs_fat.h"
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#include "driver/sdmmc_host.h"
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#include "driver/sdspi_host.h"
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#include "sdmmc_cmd.h"
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static const char *TAG = "example";
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// This example can use SDMMC and SPI peripherals to communicate with SD card.
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// By default, SDMMC peripheral is used.
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// To enable SPI mode, uncomment the following line:
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// #define USE_SPI_MODE
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// When testing SD and SPI modes, keep in mind that once the card has been
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// initialized in SPI mode, it can not be reinitialized in SD mode without
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// toggling power to the card.
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#ifdef USE_SPI_MODE
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// Pin mapping when using SPI mode.
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// With this mapping, SD card can be used both in SPI and 1-line SD mode.
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// Note that a pull-up on CS line is required in SD mode.
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#define PIN_NUM_MISO 2
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#define PIN_NUM_MOSI 15
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#define PIN_NUM_CLK 14
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#define PIN_NUM_CS 13
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#endif //USE_SPI_MODE
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void app_main(void)
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{
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ESP_LOGI(TAG, "Initializing SD card");
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#ifndef USE_SPI_MODE
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ESP_LOGI(TAG, "Using SDMMC peripheral");
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sdmmc_host_t host = SDMMC_HOST_DEFAULT();
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// To use 1-line SD mode, uncomment the following line:
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// host.flags = SDMMC_HOST_FLAG_1BIT;
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// This initializes the slot without card detect (CD) and write protect (WP) signals.
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// Modify slot_config.gpio_cd and slot_config.gpio_wp if your board has these signals.
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sdmmc_slot_config_t slot_config = SDMMC_SLOT_CONFIG_DEFAULT();
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// GPIOs 15, 2, 4, 12, 13 should have external 10k pull-ups.
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// Internal pull-ups are not sufficient. However, enabling internal pull-ups
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// does make a difference some boards, so we do that here.
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gpio_set_pull_mode(15, GPIO_PULLUP_ONLY); // CMD, needed in 4- and 1- line modes
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gpio_set_pull_mode(2, GPIO_PULLUP_ONLY); // D0, needed in 4- and 1-line modes
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gpio_set_pull_mode(4, GPIO_PULLUP_ONLY); // D1, needed in 4-line mode only
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gpio_set_pull_mode(12, GPIO_PULLUP_ONLY); // D2, needed in 4-line mode only
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gpio_set_pull_mode(13, GPIO_PULLUP_ONLY); // D3, needed in 4- and 1-line modes
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#else
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ESP_LOGI(TAG, "Using SPI peripheral");
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sdmmc_host_t host = SDSPI_HOST_DEFAULT();
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sdspi_slot_config_t slot_config = SDSPI_SLOT_CONFIG_DEFAULT();
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slot_config.gpio_miso = PIN_NUM_MISO;
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slot_config.gpio_mosi = PIN_NUM_MOSI;
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slot_config.gpio_sck = PIN_NUM_CLK;
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slot_config.gpio_cs = PIN_NUM_CS;
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// This initializes the slot without card detect (CD) and write protect (WP) signals.
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// Modify slot_config.gpio_cd and slot_config.gpio_wp if your board has these signals.
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#endif //USE_SPI_MODE
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// Options for mounting the filesystem.
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// If format_if_mount_failed is set to true, SD card will be partitioned and
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// formatted in case when mounting fails.
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esp_vfs_fat_sdmmc_mount_config_t mount_config = {
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.format_if_mount_failed = false,
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.max_files = 5
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};
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// Use settings defined above to initialize SD card and mount FAT filesystem.
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// Note: esp_vfs_fat_sdmmc_mount is an all-in-one convenience function.
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// Please check its source code and implement error recovery when developing
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// production applications.
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sdmmc_card_t* card;
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esp_err_t ret = esp_vfs_fat_sdmmc_mount("/sdcard", &host, &slot_config, &mount_config, &card);
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if (ret != ESP_OK) {
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if (ret == ESP_FAIL) {
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ESP_LOGE(TAG, "Failed to mount filesystem. "
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"If you want the card to be formatted, set format_if_mount_failed = true.");
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} else {
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ESP_LOGE(TAG, "Failed to initialize the card (%d). "
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"Make sure SD card lines have pull-up resistors in place.", ret);
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}
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return;
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}
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// Card has been initialized, print its properties
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sdmmc_card_print_info(stdout, card);
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// Use POSIX and C standard library functions to work with files.
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// First create a file.
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ESP_LOGI(TAG, "Opening file");
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FILE* f = fopen("/sdcard/hello.txt", "w");
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if (f == NULL) {
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ESP_LOGE(TAG, "Failed to open file for writing");
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return;
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}
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fprintf(f, "Hello %s!\n", card->cid.name);
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fclose(f);
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ESP_LOGI(TAG, "File written");
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// Check if destination file exists before renaming
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struct stat st;
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if (stat("/sdcard/foo.txt", &st) == 0) {
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// Delete it if it exists
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unlink("/sdcard/foo.txt");
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}
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// Rename original file
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ESP_LOGI(TAG, "Renaming file");
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if (rename("/sdcard/hello.txt", "/sdcard/foo.txt") != 0) {
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ESP_LOGE(TAG, "Rename failed");
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return;
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}
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// Open renamed file for reading
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ESP_LOGI(TAG, "Reading file");
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f = fopen("/sdcard/foo.txt", "r");
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if (f == NULL) {
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ESP_LOGE(TAG, "Failed to open file for reading");
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return;
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}
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char line[64];
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fgets(line, sizeof(line), f);
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fclose(f);
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// strip newline
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char* pos = strchr(line, '\n');
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if (pos) {
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*pos = '\0';
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}
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ESP_LOGI(TAG, "Read from file: '%s'", line);
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// All done, unmount partition and disable SDMMC or SPI peripheral
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esp_vfs_fat_sdmmc_unmount();
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ESP_LOGI(TAG, "Card unmounted");
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}
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