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examples: re-enable storage/sd_card example for ESP32-S2

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* adjust SPI initialization
* update readme file to mention ESP32-S2
This commit is contained in:
Ivan Grokhotkov 2020-03-03 17:12:31 +01:00
parent 6f7be93d53
commit 4fc3ebbdf6
3 changed files with 39 additions and 7 deletions
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1
examples/storage/sd_card/CMakeLists.txt
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@ -2,6 +2,5 @@
# in this exact order for cmake to work correctly
cmake_minimum_required(VERSION 3.5)
set(SUPPORTED_TARGETS esp32)
include($ENV{IDF_PATH}/tools/cmake/project.cmake)
project(sd_card)

25
examples/storage/sd_card/README.md
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@ -2,7 +2,7 @@
(See the README.md file in the upper level 'examples' directory for more information about examples.)
This example demonstrates how to use an SD card with ESP32. Example does the following steps:
This example demonstrates how to use an SD card with ESP32 or ESP32-S2. Example does the following steps:
1. Use an "all-in-one" `esp_vfs_fat_sdmmc_mount` function to:
- initialize SDMMC peripheral,
@ -18,6 +18,8 @@ This example support SD (SDSC, SDHC, SDXC) cards and eMMC chips.
## Hardware
### Connections for ESP32
This example runs on ESP-WROVER-KIT boards without any extra modifications required, only the SD card needs to be inserted into the slot.
Other ESP32 development boards need to be connected to SD card as follows:
@ -38,15 +40,30 @@ This example doesn't utilize card detect (CD) and write protect (WP) signals fro
With the given pinout for SPI mode, same connections between the SD card and ESP32 can be used to test both SD and SPI modes, provided that the appropriate pullups are in place.
See [the document about pullup requirements](https://docs.espressif.com/projects/esp-idf/en/latest/api-reference/peripherals/sd_pullup_requirements.html) for more details about pullup support and compatibility of modules and development boards.
In SPI mode, pins can be customized. See the initialization of ``sdspi_slot_config_t`` structure in the example code.
In SPI mode, pins can be customized. See the initialization of ``spi_bus_config_t`` and ``sdspi_slot_config_t`` structures in the example code.
### Note about GPIO2
### Connections for ESP32-S2
Note that ESP32-S2 doesn't include SD Host peripheral and only supports SD over SPI. Therefore only SCK, MOSI, MISO, CS and ground pins need to be connected.
ESP32-S2 pin | SD card pin | SPI pin | Notes
--------------|-------------|---------|------------
GPIO14 | CLK | SCK | 10k pullup
GPIO15 | CMD | MOSI | 10k pullup
GPIO2 | D0 | MISO | 10k pullup
GPIO13 | D3 | CS | 10k pullup
N/C | CD | | optional, not used in the example
N/C | WP | | optional, not used in the example
In SPI mode, pins can be customized. See the initialization of ``spi_bus_config_t`` and ``sdspi_slot_config_t`` structures in the example code.
### Note about GPIO2 (ESP32 only)
GPIO2 pin is used as a bootstrapping pin, and should be low to enter UART download mode. One way to do this is to connect GPIO0 and GPIO2 using a jumper, and then the auto-reset circuit on most development boards will pull GPIO2 low along with GPIO0, when entering download mode.
- Some boards have pulldown and/or LED on GPIO2. LED is usually ok, but pulldown will interfere with D0 signals and must be removed. Check the schematic of your development board for anything connected to GPIO2.
### Note about GPIO12
### Note about GPIO12 (ESP32 only)
GPIO12 is used as a bootstrapping pin to select output voltage of an internal regulator which powers the flash chip (VDD_SDIO). This pin has an internal pulldown so if left unconnected it will read low at reset (selecting default 3.3V operation). When adding a pullup to this pin for SD card operation, consider the following:

20
examples/storage/sd_card/main/sd_card_example_main.c
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@ -13,11 +13,14 @@
#include "esp_err.h"
#include "esp_log.h"
#include "esp_vfs_fat.h"
#include "driver/sdmmc_host.h"
#include "driver/sdspi_host.h"
#include "driver/spi_common.h"
#include "sdmmc_cmd.h"
#ifdef CONFIG_IDF_TARGET_ESP32
#include "driver/sdmmc_host.h"
#endif
static const char *TAG = "example";
#define MOUNT_POINT "/sdcard"
@ -28,7 +31,19 @@ static const char *TAG = "example";
// #define USE_SPI_MODE
// ESP32-S2 doesn't have an SD Host peripheral, always use SPI:
#ifdef CONFIG_IDF_TARGET_ESP32S2
#ifndef USE_SPI_MODE
#define USE_SPI_MODE
#endif // USE_SPI_MODE
// on ESP32-S2, DMA channel must be the same as host id
#define SPI_DMA_CHAN host.slot
#endif //CONFIG_IDF_TARGET_ESP32S2
// DMA channel to be used by the SPI peripheral
#ifndef SPI_DMA_CHAN
#define SPI_DMA_CHAN 1
#endif //SPI_DMA_CHAN
// When testing SD and SPI modes, keep in mind that once the card has been
// initialized in SPI mode, it can not be reinitialized in SD mode without
@ -105,7 +120,8 @@ void app_main(void)
// This initializes the slot without card detect (CD) and write protect (WP) signals.
// Modify slot_config.gpio_cd and slot_config.gpio_wp if your board has these signals.
sdspi_device_config_t slot_config = SDSPI_DEVICE_CONFIG_DEFAULT();
slot_config.gpio_cs = PIN_NUM_CS;
slot_config.gpio_cs = PIN_NUM_CS;
slot_config.host_id = host.slot;
ret = esp_vfs_fat_sdspi_mount(mount_point, &host, &slot_config, &mount_config, &card);
#endif //USE_SPI_MODE