Merge branch 'feat/sdio_pullup' into 'master'

feature(sdio): add features to make SDIO slave compatible with more devkits

See merge request idf/esp-idf!2454

components/driver/include/driver/sdio_slave.h

@@ -20,7 +20,7 @@
 #include "esp_err.h"
 #include "rom/queue.h"
 
-#include "soc/host_reg.h"
+#include "soc/sdio_slave_periph.h"
 
 #ifdef __cplusplus
 extern "C" {
@@ -71,6 +71,23 @@ typedef struct {
                             ///< All data that do not fully fill a buffer is still counted as one buffer. E.g. 10 bytes data costs 2 buffers if the size is 8 bytes per buffer.
                             ///< Buffer size of the slave pre-defined between host and slave before communication. All receive buffer given to the driver should be larger than this.
     sdio_event_cb_t     event_cb;           ///< when the host interrupts slave, this callback will be called with interrupt number (0-7).
+    uint32_t            flags; ///< Features to be enabled for the slave, combinations of ``SDIO_SLAVE_FLAG_*``.
+#define SDIO_SLAVE_FLAG_DAT2_DISABLED       BIT(0)      /**< It is required by the SD specification that all 4 data 
+        lines should be used and pulled up even in 1-bit mode or SPI mode. However, as a feature, the user can speicfy 
+        this flag to make use of DAT2 pin in 1-bit mode. Note that the host cannot read CCCR registers to know we don't 
+        support 4-bit mode anymore, please do this at your own risk.
+        */
+#define SDIO_SLAVE_FLAG_HOST_INTR_DISABLED  BIT(1)      /**< The DAT1 line is used as the interrupt line in SDIO        
+        protocol. However, as a feature, the user can speicfy this flag to make use of DAT1 pin of the slave in 1-bit 
+        mode. Note that the host has to do polling to the interrupt registers to know whether there are interrupts from
+        the slave. And it cannot read CCCR registers to know we don't support 4-bit mode anymore, please do this at 
+        your own risk.
+        */
+#define SDIO_SLAVE_FLAG_INTERNAL_PULLUP     BIT(2)      /**< Enable internal pullups for enabled pins. It is required 
+        by the SD specification that all the 4 data lines should be pulled up even in 1-bit mode or SPI mode. Note that 
+        the internal pull-ups are not sufficient for stable communication, please do connect external pull-ups on the 
+        bus. This is only for example and debug use.
+        */
 } sdio_slave_config_t;
 
 /** Handle of a receive buffer, register a handle by calling ``sdio_slave_recv_register_buf``. Use the handle to load the buffer to the

components/driver/include/driver/sdmmc_host.h

@@ -55,6 +55,12 @@ typedef struct {
     gpio_num_t gpio_cd;     ///< GPIO number of card detect signal
     gpio_num_t gpio_wp;     ///< GPIO number of write protect signal
     uint8_t width;          ///< Bus width used by the slot (might be less than the max width supported)
+    uint32_t flags;         ///< Features used by this slot
+#define SDMMC_SLOT_FLAG_INTERNAL_PULLUP  BIT(0) 
+        /**< Enable internal pullups on enabled pins. The internal pullups
+         are insufficient however, please make sure external pullups are
+         connected on the bus. This is for debug / example purpose only.
+         */
 } sdmmc_slot_config_t;
 
 #define SDMMC_SLOT_NO_CD      ((gpio_num_t) -1)     ///< indicates that card detect line is not used
@@ -68,6 +74,7 @@ typedef struct {
     .gpio_cd = SDMMC_SLOT_NO_CD, \
     .gpio_wp = SDMMC_SLOT_NO_WP, \
     .width   = SDMMC_SLOT_WIDTH_DEFAULT, \
+    .flags = 0, \
 }
 
 /**
@@ -199,6 +206,23 @@ esp_err_t sdmmc_host_io_int_wait(int slot, TickType_t timeout_ticks);
  */
 esp_err_t sdmmc_host_deinit();
 
+/**
+ * @brief Enable the pull-ups of sd pins.
+ * 
+ * @note You should always place actual pullups on the lines instead of using
+ * this function. Internal pullup resistance are high and not sufficient, may
+ * cause instability in products. This is for debug or examples only.
+ * 
+ * @param slot Slot to use, normally set it to 1.
+ * @param width Bit width of your configuration, 1 or 4.
+ * 
+ * @return
+ *      - ESP_OK: if success
+ *      - ESP_ERR_INVALID_ARG: if configured width larger than maximum the slot can
+ *              support
+ */
+esp_err_t sdmmc_host_pullup_en(int slot, int width);
+
 #ifdef __cplusplus
 }
 #endif

components/driver/sdio_slave.c

@@ -86,10 +86,7 @@ The driver of FIFOs works as below:
 
 #include <string.h>
 #include "driver/sdio_slave.h"
-#include "soc/slc_struct.h"
-#include "soc/slc_reg.h"
-#include "soc/host_struct.h"
-#include "soc/hinf_struct.h"
+#include "soc/sdio_slave_periph.h"
 #include "rom/lldesc.h"
 #include "esp_log.h"
 #include "esp_intr_alloc.h"
@@ -119,41 +116,6 @@ typedef enum {
     STATE_SENDING = 3,
 } send_state_t;
 
-typedef struct {
-    uint32_t clk;
-    uint32_t cmd;
-    uint32_t d0;
-    uint32_t d1;
-    uint32_t d2;
-    uint32_t d3;
-    int      func;
-} sdio_slave_slot_info_t ;
-
-// I/O slot of sdio slave:
-// 0: GPIO 6, 11, 7, 8, 9, 10,
-// 1: GPIO 14, 15, 2, 4, 12, 13 for CLK, CMD, D0, D1, D2, D3 respectively.
-// only one peripheral for SDIO and only one slot can work at the same time.
-// currently slot 0 is occupied by SPI for flash
-static const sdio_slave_slot_info_t s_slot_info[2]  = {
-    {
-        .clk = PERIPHS_IO_MUX_SD_CLK_U,
-        .cmd = PERIPHS_IO_MUX_SD_CMD_U,
-        .d0 = PERIPHS_IO_MUX_SD_DATA0_U,
-        .d1 = PERIPHS_IO_MUX_SD_DATA1_U,
-        .d2 = PERIPHS_IO_MUX_SD_DATA2_U,
-        .d3 = PERIPHS_IO_MUX_SD_DATA3_U,
-        .func = 0,
-    }, {
-        .clk = PERIPHS_IO_MUX_MTMS_U,
-        .cmd = PERIPHS_IO_MUX_MTDO_U,
-        .d0 = PERIPHS_IO_MUX_GPIO2_U,
-        .d1 = PERIPHS_IO_MUX_GPIO4_U,
-        .d2 = PERIPHS_IO_MUX_MTDI_U,
-        .d3 = PERIPHS_IO_MUX_MTCK_U,
-        .func = 4,
-    },
-};
-
 // first 3 WORDs of this struct is defined by and compatible to the DMA link list format.
 // sdio_slave_buf_handle_t is of type buf_desc_t*;
 typedef struct  buf_desc_s{
@@ -225,7 +187,7 @@ typedef struct {
     /*------- receiving ---------------*/
     buf_stailq_t    recv_link_list; // now ready to/already hold data
     buf_tailq_t     recv_reg_list;  // removed from the link list, registered but not used now
-    buf_desc_t*     recv_cur_ret;
+    volatile buf_desc_t*     recv_cur_ret;   // next desc to return, NULL if all loaded descriptors are returned
     portMUX_TYPE    recv_spinlock;
 } sdio_context_t;
 
@@ -499,13 +461,21 @@ no_mem:
     return ESP_ERR_NO_MEM;
 }
 
-static inline void configure_pin(uint32_t io_mux_reg, uint32_t func)
+static void configure_pin(int pin, uint32_t func, bool pullup)
 {
     const int sdmmc_func = func;
     const int drive_strength = 3;
-    PIN_INPUT_ENABLE(io_mux_reg);
-    PIN_FUNC_SELECT(io_mux_reg, sdmmc_func);
-    PIN_SET_DRV(io_mux_reg, drive_strength);
+    assert(pin!=-1);
+    uint32_t reg = GPIO_PIN_MUX_REG[pin];
+    assert(reg!=UINT32_MAX);
+
+    PIN_INPUT_ENABLE(reg);
+    PIN_FUNC_SELECT(reg, sdmmc_func);
+    PIN_SET_DRV(reg, drive_strength);
+    if (pullup) {
+        gpio_pullup_en(pin);
+        gpio_pulldown_dis(pin);
+    }
 }
 
 static inline esp_err_t sdio_slave_hw_init(sdio_slave_config_t *config)
@@ -514,13 +484,20 @@ static inline esp_err_t sdio_slave_hw_init(sdio_slave_config_t *config)
     SLC.slc0_int_ena.val = 0;
 
     //initialize pin
-    const sdio_slave_slot_info_t *slot = &s_slot_info[1];
-    configure_pin(slot->clk, slot->func);
-    configure_pin(slot->cmd, slot->func);
-    configure_pin(slot->d0, slot->func);
-    configure_pin(slot->d1, slot->func);
-    configure_pin(slot->d2, slot->func);
-    configure_pin(slot->d3, slot->func);
+    const sdio_slave_slot_info_t *slot = &sdio_slave_slot_info[1];
+
+    bool pullup = config->flags & SDIO_SLAVE_FLAG_INTERNAL_PULLUP;
+    configure_pin(slot->clk_gpio, slot->func, false);   //clk doesn't need a pullup
+    configure_pin(slot->cmd_gpio, slot->func, pullup);
+    configure_pin(slot->d0_gpio, slot->func, pullup);
+    if ((config->flags & SDIO_SLAVE_FLAG_HOST_INTR_DISABLED)==0) {
+        configure_pin(slot->d1_gpio, slot->func, pullup);
+    } 
+    if ((config->flags & SDIO_SLAVE_FLAG_DAT2_DISABLED)==0) {
+       configure_pin(slot->d2_gpio, slot->func, pullup); 
+    }
+    configure_pin(slot->d3_gpio, slot->func, pullup);
+
     //enable module and config
     periph_module_reset(PERIPH_SDIO_SLAVE_MODULE);
     periph_module_enable(PERIPH_SDIO_SLAVE_MODULE);
@@ -1160,8 +1137,6 @@ static void sdio_intr_recv(void* arg)
     portBASE_TYPE yield = 0;
     if ( SLC.slc0_int_raw.tx_done ) {
         SLC.slc0_int_clr.tx_done = 1;
-        assert( context.recv_cur_ret != NULL );
-
         while ( context.recv_cur_ret && context.recv_cur_ret->owner == 0 ) {
             // This may cause the ``cur_ret`` pointer to be NULL, indicating the list is empty,
             // in this case the ``tx_done`` should happen no longer until new desc is appended.
@@ -1186,15 +1161,24 @@ esp_err_t sdio_slave_recv_load_buf(sdio_slave_buf_handle_t handle)
     desc->owner = 1;
     desc->not_receiving = 0; //manually remove the prev link (by set not_receiving=0), to indicate this is in the queue
 
-    // 1. If all desc are returned in the ISR, the pointer is moved to NULL. The pointer is set to the newly appended desc here.
-    // 2. If the pointer is move to some not-returned desc (maybe the one appended here), do nothing.
-    // The ``cur_ret`` pointer must be checked and set after new desc appended to the list, or the pointer setting may fail.
+    buf_desc_t *const tail = STAILQ_LAST(queue, buf_desc_s, qe);
+
     STAILQ_INSERT_TAIL( queue, desc, qe );
-    if ( context.recv_cur_ret == NULL ) {
+    if (tail == NULL || (tail->owner == 0)) {
+        //in this case we have to set the ret pointer
+        if (tail != NULL) {
+            /* if the owner of the tail is returned to the software, the ISR is
+             * expect to write this pointer to NULL in a short time, wait until
+             * that and set new value for this pointer
+             */
+            while (context.recv_cur_ret != NULL) {}
+        }
+        assert(context.recv_cur_ret == NULL);
         context.recv_cur_ret = desc;
     }
+    assert(context.recv_cur_ret != NULL);
 
-    if ( desc == STAILQ_FIRST(queue) ) {
+    if (tail == NULL) {
         //no one in the ll, start new ll operation.
         SLC.slc0_tx_link.addr = (uint32_t)desc;
         SLC.slc0_tx_link.start = 1;

components/driver/sdmmc_host.c

@@ -17,76 +17,21 @@
 #include <sys/param.h>
 #include "esp_log.h"
 #include "esp_intr_alloc.h"
-#include "soc/sdmmc_struct.h"
-#include "soc/sdmmc_reg.h"
 #include "soc/io_mux_reg.h"
-#include "soc/gpio_sig_map.h"
 #include "rom/gpio.h"
 #include "driver/gpio.h"
 #include "driver/sdmmc_host.h"
 #include "driver/periph_ctrl.h"
 #include "sdmmc_private.h"
 #include "freertos/semphr.h"
+#include "soc/sdmmc_periph.h"
 
 #define SDMMC_EVENT_QUEUE_LENGTH 32
 
-typedef struct {
-    uint32_t clk;
-    uint32_t cmd;
-    uint32_t d0;
-    uint32_t d1;
-    uint32_t d2;
-    uint32_t d3;
-    uint32_t d4;
-    uint32_t d5;
-    uint32_t d6;
-    uint32_t d7;
-    uint8_t d1_gpio;
-    uint8_t d3_gpio;
-    uint8_t card_detect;
-    uint8_t write_protect;
-    uint8_t card_int;
-    uint8_t width;
-} sdmmc_slot_info_t;
-
 
 static void sdmmc_isr(void* arg);
 static void sdmmc_host_dma_init();
 
-static const sdmmc_slot_info_t s_slot_info[2]  = {
-    {
-        .clk = PERIPHS_IO_MUX_SD_CLK_U,
-        .cmd = PERIPHS_IO_MUX_SD_CMD_U,
-        .d0 = PERIPHS_IO_MUX_SD_DATA0_U,
-        .d1 = PERIPHS_IO_MUX_SD_DATA1_U,
-        .d2 = PERIPHS_IO_MUX_SD_DATA2_U,
-        .d3 = PERIPHS_IO_MUX_SD_DATA3_U,
-        .d1_gpio = 8,
-        .d3_gpio = 10,
-        .d4 = PERIPHS_IO_MUX_GPIO16_U,
-        .d5 = PERIPHS_IO_MUX_GPIO17_U,
-        .d6 = PERIPHS_IO_MUX_GPIO5_U,
-        .d7 = PERIPHS_IO_MUX_GPIO18_U,
-        .card_detect = HOST_CARD_DETECT_N_1_IDX,
-        .write_protect = HOST_CARD_WRITE_PRT_1_IDX,
-        .card_int = HOST_CARD_INT_N_1_IDX,
-        .width = 8
-    },
-    {
-        .clk = PERIPHS_IO_MUX_MTMS_U,
-        .cmd = PERIPHS_IO_MUX_MTDO_U,
-        .d0 = PERIPHS_IO_MUX_GPIO2_U,
-        .d1 = PERIPHS_IO_MUX_GPIO4_U,
-        .d2 = PERIPHS_IO_MUX_MTDI_U,
-        .d3 = PERIPHS_IO_MUX_MTCK_U,
-        .d1_gpio = 4,
-        .d3_gpio = 13,
-        .card_detect = HOST_CARD_DETECT_N_2_IDX,
-        .write_protect = HOST_CARD_WRITE_PRT_2_IDX,
-        .card_int = HOST_CARD_INT_N_2_IDX,
-        .width = 4
-    }
-};
 
 static const char* TAG = "sdmmc_periph";
 static intr_handle_t s_intr_handle;
@@ -340,18 +285,24 @@ esp_err_t sdmmc_host_init()
     return ESP_OK;
 }
 
-
-static inline void configure_pin(uint32_t io_mux_reg)
+static void configure_pin(int pin)
 {
     const int sdmmc_func = 3;
     const int drive_strength = 3;
-    PIN_INPUT_ENABLE(io_mux_reg);
-    PIN_FUNC_SELECT(io_mux_reg, sdmmc_func);
-    PIN_SET_DRV(io_mux_reg, drive_strength);
+    assert(pin!=-1);
+    uint32_t reg = GPIO_PIN_MUX_REG[pin];
+    assert(reg != UINT32_MAX);
+    PIN_INPUT_ENABLE(reg);
+    PIN_FUNC_SELECT(reg, sdmmc_func);
+    PIN_SET_DRV(reg, drive_strength);
 }
 
 esp_err_t sdmmc_host_init_slot(int slot, const sdmmc_slot_config_t* slot_config)
 {
+    bool pullup = slot_config->flags & SDMMC_SLOT_FLAG_INTERNAL_PULLUP;
+    if (pullup) {
+        sdmmc_host_pullup_en(slot, slot_config->width);
+    }
     if (!s_intr_handle) {
         return ESP_ERR_INVALID_STATE;
     }
@@ -366,7 +317,7 @@ esp_err_t sdmmc_host_init_slot(int slot, const sdmmc_slot_config_t* slot_config)
     uint8_t slot_width = slot_config->width;
 
     // Configure pins
-    const sdmmc_slot_info_t* pslot = &s_slot_info[slot];
+    const sdmmc_slot_info_t* pslot = &sdmmc_slot_info[slot];
 
     if (slot_width == SDMMC_SLOT_WIDTH_DEFAULT) {
         slot_width = pslot->width;
@@ -376,13 +327,13 @@ esp_err_t sdmmc_host_init_slot(int slot, const sdmmc_slot_config_t* slot_config)
     }
     s_slot_width[slot] = slot_width;
 
-    configure_pin(pslot->clk);
-    configure_pin(pslot->cmd);
-    configure_pin(pslot->d0);
+    configure_pin(pslot->clk_gpio);
+    configure_pin(pslot->cmd_gpio);
+    configure_pin(pslot->d0_gpio);
 
     if (slot_width >= 4) {
-        configure_pin(pslot->d1);
-        configure_pin(pslot->d2);
+        configure_pin(pslot->d1_gpio);
+        configure_pin(pslot->d2_gpio);
         //force pull-up D3 to make slave detect SD mode. connect to peripheral after width configuration.
         gpio_config_t gpio_conf = {
             .pin_bit_mask = BIT(pslot->d3_gpio),
@@ -394,10 +345,10 @@ esp_err_t sdmmc_host_init_slot(int slot, const sdmmc_slot_config_t* slot_config)
         gpio_config( &gpio_conf );
         gpio_set_level( pslot->d3_gpio, 1 );
         if (slot_width == 8) {
-            configure_pin(pslot->d4);
-            configure_pin(pslot->d5);
-            configure_pin(pslot->d6);
-            configure_pin(pslot->d7);
+            configure_pin(pslot->d4_gpio);
+            configure_pin(pslot->d5_gpio);
+            configure_pin(pslot->d6_gpio);
+            configure_pin(pslot->d7_gpio);
         }
     }
 
@@ -482,7 +433,7 @@ esp_err_t sdmmc_host_set_bus_width(int slot, size_t width)
     if (!(slot == 0 || slot == 1)) {
         return ESP_ERR_INVALID_ARG;
     }
-    if (s_slot_info[slot].width < width) {
+    if (sdmmc_slot_info[slot].width < width) {
         return ESP_ERR_INVALID_ARG;
     }
     const uint16_t mask = BIT(slot);
@@ -492,10 +443,10 @@ esp_err_t sdmmc_host_set_bus_width(int slot, size_t width)
     } else if (width == 4) {
         SDMMC.ctype.card_width_8 &= ~mask;
         SDMMC.ctype.card_width |= mask;
-        configure_pin(s_slot_info[slot].d3);   // D3 was set to GPIO high to force slave into SD 1-bit mode, until 4-bit mode is set
+        configure_pin(sdmmc_slot_info[slot].d3_gpio);   // D3 was set to GPIO high to force slave into SD 1-bit mode, until 4-bit mode is set
     } else if (width == 8){
         SDMMC.ctype.card_width_8 |= mask;
-        configure_pin(s_slot_info[slot].d3);   // D3 was set to GPIO high to force slave into SD 1-bit mode, until 4-bit mode is set
+        configure_pin(sdmmc_slot_info[slot].d3_gpio);   // D3 was set to GPIO high to force slave into SD 1-bit mode, until 4-bit mode is set
     } else {
         return ESP_ERR_INVALID_ARG;
     }
@@ -550,7 +501,7 @@ void sdmmc_host_dma_resume()
 
 esp_err_t sdmmc_host_io_int_enable(int slot)
 {
-    configure_pin(s_slot_info[slot].d1);
+    configure_pin(sdmmc_slot_info[slot].d1_gpio);
     return ESP_OK;
 }
 
@@ -566,7 +517,7 @@ esp_err_t sdmmc_host_io_int_wait(int slot, TickType_t timeout_ticks)
 
     SDMMC.intmask.sdio &= ~BIT(slot);   /* Disable SDIO interrupt */
     SDMMC.rintsts.sdio = BIT(slot);
-    if (gpio_get_level(s_slot_info[slot].d1_gpio) == 0) {
+    if (gpio_get_level(sdmmc_slot_info[slot].d1_gpio) == 0) {
         return ESP_OK;
     }
     /* Otherwise, need to wait for an interrupt. Since D1 was high,
@@ -627,3 +578,34 @@ static void sdmmc_isr(void* arg) {
     }
 }
 
+esp_err_t sdmmc_host_pullup_en(int slot, int width)
+{
+    if (width > sdmmc_slot_info[slot].width) {
+        //in esp32 we only support 8 bit in slot 0, note this is occupied by the flash by default
+        return ESP_ERR_INVALID_ARG;
+    }
+    //according to the spec, the host control the clk, we don't to pull it up here
+    gpio_pullup_en(sdmmc_slot_info[slot].cmd_gpio);
+    gpio_pulldown_dis(sdmmc_slot_info[slot].cmd_gpio);
+    gpio_pullup_en(sdmmc_slot_info[slot].d0_gpio);
+    gpio_pulldown_dis(sdmmc_slot_info[slot].d0_gpio);
+    if (width >= 4) {
+        gpio_pullup_en(sdmmc_slot_info[slot].d1_gpio);
+        gpio_pulldown_dis(sdmmc_slot_info[slot].d1_gpio);
+        gpio_pullup_en(sdmmc_slot_info[slot].d2_gpio);
+        gpio_pulldown_dis(sdmmc_slot_info[slot].d2_gpio);
+        gpio_pullup_en(sdmmc_slot_info[slot].d3_gpio);
+        gpio_pulldown_dis(sdmmc_slot_info[slot].d3_gpio);
+    }
+    if (width == 8) {
+        gpio_pullup_en(sdmmc_slot_info[slot].d4_gpio);
+        gpio_pulldown_dis(sdmmc_slot_info[slot].d4_gpio);
+        gpio_pullup_en(sdmmc_slot_info[slot].d5_gpio);
+        gpio_pulldown_dis(sdmmc_slot_info[slot].d5_gpio);
+        gpio_pullup_en(sdmmc_slot_info[slot].d6_gpio);
+        gpio_pulldown_dis(sdmmc_slot_info[slot].d6_gpio);
+        gpio_pullup_en(sdmmc_slot_info[slot].d7_gpio);
+        gpio_pulldown_dis(sdmmc_slot_info[slot].d7_gpio);
+    }
+    return ESP_OK;
+}

components/driver/sdmmc_private.h

@@ -19,7 +19,7 @@
 #include "esp_err.h"
 #include "freertos/FreeRTOS.h"
 #include "freertos/queue.h"
-#include "soc/sdmmc_struct.h"
+#include "soc/sdmmc_periph.h"
 
 typedef struct {
     uint32_t sdmmc_status;      ///< masked SDMMC interrupt status

components/driver/sdmmc_transaction.c

@@ -19,8 +19,7 @@
 #include "freertos/FreeRTOS.h"
 #include "freertos/queue.h"
 #include "freertos/semphr.h"
-#include "soc/sdmmc_reg.h"
-#include "soc/sdmmc_struct.h"
+#include "soc/sdmmc_periph.h"
 #include "soc/soc_memory_layout.h"
 #include "driver/sdmmc_types.h"
 #include "driver/sdmmc_defs.h"

components/driver/sdspi_transaction.c

@@ -17,7 +17,7 @@
 #include "esp_log.h"
 #include "sys/lock.h"
 #include "soc/sdmmc_reg.h"
-#include "soc/sdmmc_struct.h"
+#include "soc/sdmmc_periph.h"
 #include "driver/sdmmc_types.h"
 #include "driver/sdmmc_defs.h"
 #include "driver/sdmmc_host.h"

components/soc/esp32/include/soc/sdio_slave_pins.h

@@ -0,0 +1,34 @@
+// Copyright 2015-2018 Espressif Systems (Shanghai) PTE LTD
+//
+// Licensed under the Apache License, Version 2.0 (the "License");
+// you may not use this file except in compliance with the License.
+// You may obtain a copy of the License at
+
+//     http://www.apache.org/licenses/LICENSE-2.0
+//
+// Unless required by applicable law or agreed to in writing, software
+// distributed under the License is distributed on an "AS IS" BASIS,
+// WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+// See the License for the specific language governing permissions and
+// limitations under the License.
+
+#ifndef _SOC_SDIO_SLAVE_PINS_H_
+#define _SOC_SDIO_SLAVE_PINS_H_
+
+#define SDIO_SLAVE_SLOT0_IOMUX_PIN_NUM_CLK  6
+#define SDIO_SLAVE_SLOT0_IOMUX_PIN_NUM_CMD  11
+#define SDIO_SLAVE_SLOT0_IOMUX_PIN_NUM_D0   7
+#define SDIO_SLAVE_SLOT0_IOMUX_PIN_NUM_D1   8
+#define SDIO_SLAVE_SLOT0_IOMUX_PIN_NUM_D2   9
+#define SDIO_SLAVE_SLOT0_IOMUX_PIN_NUM_D3   10
+#define SDIO_SLAVE_SLOT0_FUNC               0
+
+#define SDIO_SLAVE_SLOT1_IOMUX_PIN_NUM_CLK  14
+#define SDIO_SLAVE_SLOT1_IOMUX_PIN_NUM_CMD  15
+#define SDIO_SLAVE_SLOT1_IOMUX_PIN_NUM_D0   2
+#define SDIO_SLAVE_SLOT1_IOMUX_PIN_NUM_D1   4
+#define SDIO_SLAVE_SLOT1_IOMUX_PIN_NUM_D2   12
+#define SDIO_SLAVE_SLOT1_IOMUX_PIN_NUM_D3   13
+#define SDIO_SLAVE_SLOT1_FUNC               4
+
+#endif /* _SOC_SDIO_SLAVE_PINS_H_ */

components/soc/esp32/include/soc/sdmmc_pins.h

@@ -0,0 +1,38 @@
+// Copyright 2015-2018 Espressif Systems (Shanghai) PTE LTD
+//
+// Licensed under the Apache License, Version 2.0 (the "License");
+// you may not use this file except in compliance with the License.
+// You may obtain a copy of the License at
+
+//     http://www.apache.org/licenses/LICENSE-2.0
+//
+// Unless required by applicable law or agreed to in writing, software
+// distributed under the License is distributed on an "AS IS" BASIS,
+// WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+// See the License for the specific language governing permissions and
+// limitations under the License.
+
+#ifndef _SOC_SDMMC_PINS_H_
+#define _SOC_SDMMC_PINS_H_
+
+#define SDMMC_SLOT0_IOMUX_PIN_NUM_CLK  6
+#define SDMMC_SLOT0_IOMUX_PIN_NUM_CMD  11
+#define SDMMC_SLOT0_IOMUX_PIN_NUM_D0   7
+#define SDMMC_SLOT0_IOMUX_PIN_NUM_D1   8
+#define SDMMC_SLOT0_IOMUX_PIN_NUM_D2   9
+#define SDMMC_SLOT0_IOMUX_PIN_NUM_D3   10
+#define SDMMC_SLOT0_IOMUX_PIN_NUM_D4   16
+#define SDMMC_SLOT0_IOMUX_PIN_NUM_D5   17
+#define SDMMC_SLOT0_IOMUX_PIN_NUM_D6   5
+#define SDMMC_SLOT0_IOMUX_PIN_NUM_D7   18
+#define SDMMC_SLOT0_FUNC               0
+
+#define SDMMC_SLOT1_IOMUX_PIN_NUM_CLK  14
+#define SDMMC_SLOT1_IOMUX_PIN_NUM_CMD  15
+#define SDMMC_SLOT1_IOMUX_PIN_NUM_D0   2
+#define SDMMC_SLOT1_IOMUX_PIN_NUM_D1   4
+#define SDMMC_SLOT1_IOMUX_PIN_NUM_D2   12
+#define SDMMC_SLOT1_IOMUX_PIN_NUM_D3   13
+#define SDMMC_SLOT1_FUNC               4
+
+#endif /* _SOC_SDMMC_PINS_H_ */

components/soc/esp32/sdio_slave_periph.c

@@ -0,0 +1,43 @@
+// Copyright 2015-2018 Espressif Systems (Shanghai) PTE LTD
+//
+// Licensed under the Apache License, Version 2.0 (the "License");
+// you may not use this file except in compliance with the License.
+// You may obtain a copy of the License at
+
+//     http://www.apache.org/licenses/LICENSE-2.0
+//
+// Unless required by applicable law or agreed to in writing, software
+// distributed under the License is distributed on an "AS IS" BASIS,
+// WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+// See the License for the specific language governing permissions and
+// limitations under the License.
+
+#include <stdint.h>
+#include "soc/sdio_slave_periph.h"
+#include "soc/io_mux_reg.h"
+#include "soc/sdio_slave_pins.h"
+
+// I/O slot of sdio slave:
+// 0: GPIO 6, 11, 7, 8, 9, 10,
+// 1: GPIO 14, 15, 2, 4, 12, 13 for CLK, CMD, D0, D1, D2, D3 respectively.
+// only one peripheral for SDIO and only one slot can work at the same time.
+// currently slot 0 is occupied by SPI for flash
+const sdio_slave_slot_info_t sdio_slave_slot_info[2]  = {
+    {
+        .clk_gpio = SDIO_SLAVE_SLOT0_IOMUX_PIN_NUM_CLK,
+        .cmd_gpio = SDIO_SLAVE_SLOT0_IOMUX_PIN_NUM_CMD,
+        .d0_gpio = SDIO_SLAVE_SLOT0_IOMUX_PIN_NUM_D0,
+        .d1_gpio = SDIO_SLAVE_SLOT0_IOMUX_PIN_NUM_D1,
+        .d2_gpio = SDIO_SLAVE_SLOT0_IOMUX_PIN_NUM_D2,
+        .d3_gpio = SDIO_SLAVE_SLOT0_IOMUX_PIN_NUM_D3,
+        .func = SDIO_SLAVE_SLOT0_FUNC,
+    }, {
+        .clk_gpio = SDIO_SLAVE_SLOT1_IOMUX_PIN_NUM_CLK,
+        .cmd_gpio = SDIO_SLAVE_SLOT1_IOMUX_PIN_NUM_CMD,
+        .d0_gpio = SDIO_SLAVE_SLOT1_IOMUX_PIN_NUM_D0,
+        .d1_gpio = SDIO_SLAVE_SLOT1_IOMUX_PIN_NUM_D1,
+        .d2_gpio = SDIO_SLAVE_SLOT1_IOMUX_PIN_NUM_D2,
+        .d3_gpio = SDIO_SLAVE_SLOT1_IOMUX_PIN_NUM_D3,
+        .func = SDIO_SLAVE_SLOT1_FUNC,
+    },
+};

components/soc/esp32/sdmmc_periph.c

@@ -0,0 +1,50 @@
+// Copyright 2015-2018 Espressif Systems (Shanghai) PTE LTD
+//
+// Licensed under the Apache License, Version 2.0 (the "License");
+// you may not use this file except in compliance with the License.
+// You may obtain a copy of the License at
+
+//     http://www.apache.org/licenses/LICENSE-2.0
+//
+// Unless required by applicable law or agreed to in writing, software
+// distributed under the License is distributed on an "AS IS" BASIS,
+// WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+// See the License for the specific language governing permissions and
+// limitations under the License.
+
+#include "soc/sdmmc_periph.h"
+
+const sdmmc_slot_info_t sdmmc_slot_info[2]  = {
+    {
+        .clk_gpio = SDMMC_SLOT0_IOMUX_PIN_NUM_CLK,
+        .cmd_gpio = SDMMC_SLOT0_IOMUX_PIN_NUM_CMD,
+        .d0_gpio = SDMMC_SLOT0_IOMUX_PIN_NUM_D0,
+        .d1_gpio = SDMMC_SLOT0_IOMUX_PIN_NUM_D1,
+        .d2_gpio = SDMMC_SLOT0_IOMUX_PIN_NUM_D2,
+        .d3_gpio = SDMMC_SLOT0_IOMUX_PIN_NUM_D3,
+        .d4_gpio = SDMMC_SLOT0_IOMUX_PIN_NUM_D4,
+        .d5_gpio = SDMMC_SLOT0_IOMUX_PIN_NUM_D5,
+        .d6_gpio = SDMMC_SLOT0_IOMUX_PIN_NUM_D6,
+        .d7_gpio = SDMMC_SLOT0_IOMUX_PIN_NUM_D7,
+        .card_detect = HOST_CARD_DETECT_N_1_IDX,
+        .write_protect = HOST_CARD_WRITE_PRT_1_IDX,
+        .card_int = HOST_CARD_INT_N_1_IDX,
+        .width = 8
+    },
+    {
+        .clk_gpio = SDMMC_SLOT1_IOMUX_PIN_NUM_CLK,
+        .cmd_gpio = SDMMC_SLOT1_IOMUX_PIN_NUM_CMD,
+        .d0_gpio = SDMMC_SLOT1_IOMUX_PIN_NUM_D0,
+        .d1_gpio = SDMMC_SLOT1_IOMUX_PIN_NUM_D1,
+        .d2_gpio = SDMMC_SLOT1_IOMUX_PIN_NUM_D2,
+        .d3_gpio = SDMMC_SLOT1_IOMUX_PIN_NUM_D3,
+        .d4_gpio = -1,  //slot1 has no D4-7
+        .d5_gpio = -1,
+        .d6_gpio = -1,
+        .d7_gpio = -1,
+        .card_detect = HOST_CARD_DETECT_N_2_IDX,
+        .write_protect = HOST_CARD_WRITE_PRT_2_IDX,
+        .card_int = HOST_CARD_INT_N_2_IDX,
+        .width = 4
+    }
+};

components/soc/include/soc/sdio_slave_periph.h

@@ -0,0 +1,49 @@
+// Copyright 2015-2018 Espressif Systems (Shanghai) PTE LTD
+//
+// Licensed under the Apache License, Version 2.0 (the "License");
+// you may not use this file except in compliance with the License.
+// You may obtain a copy of the License at
+
+//     http://www.apache.org/licenses/LICENSE-2.0
+//
+// Unless required by applicable law or agreed to in writing, software
+// distributed under the License is distributed on an "AS IS" BASIS,
+// WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+// See the License for the specific language governing permissions and
+// limitations under the License.
+
+#ifndef _SOC_SDIO_SLAVE_PERIPH_H_
+#define _SOC_SDIO_SLAVE_PERIPH_H_
+
+#include <stdint.h>
+//include soc related (generated) definitions
+#include "soc/sdio_slave_pins.h"
+#include "soc/slc_reg.h"
+#include "soc/slc_struct.h"
+#include "soc/host_reg.h"
+#include "soc/host_struct.h"
+#include "soc/hinf_reg.h"
+#include "soc/hinf_struct.h"
+
+#ifdef __cplusplus
+extern "C" {
+#endif
+
+/** pin and signal information of each slot */
+typedef struct {
+    uint32_t clk_gpio;
+    uint32_t cmd_gpio;
+    uint32_t d0_gpio;
+    uint32_t d1_gpio;
+    uint32_t d2_gpio;
+    uint32_t d3_gpio;
+    int      func;
+} sdio_slave_slot_info_t;
+
+extern const sdio_slave_slot_info_t sdio_slave_slot_info[];
+
+#ifdef __cplusplus
+}
+#endif
+
+#endif /* _SOC_SDIO_SLAVE_PERIPH_H_ */

components/soc/include/soc/sdmmc_periph.h

@@ -0,0 +1,53 @@
+// Copyright 2015-2018 Espressif Systems (Shanghai) PTE LTD
+//
+// Licensed under the Apache License, Version 2.0 (the "License");
+// you may not use this file except in compliance with the License.
+// You may obtain a copy of the License at
+
+//     http://www.apache.org/licenses/LICENSE-2.0
+//
+// Unless required by applicable law or agreed to in writing, software
+// distributed under the License is distributed on an "AS IS" BASIS,
+// WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+// See the License for the specific language governing permissions and
+// limitations under the License.
+
+#ifndef _SOC_SDMMC_PERIPH_H_
+#define _SOC_SDMMC_PERIPH_H_
+
+#include <stdint.h>
+//include soc related (generated) definitions
+#include "soc/sdmmc_pins.h"
+#include "soc/sdmmc_reg.h"
+#include "soc/sdmmc_struct.h"
+#include "soc/gpio_sig_map.h"
+
+#ifdef __cplusplus
+extern "C" {
+#endif
+
+typedef struct {
+    uint8_t clk_gpio;
+    uint8_t cmd_gpio;
+    uint8_t d0_gpio;
+    uint8_t d1_gpio;
+    uint8_t d2_gpio;
+    uint8_t d3_gpio;
+    uint8_t d4_gpio;
+    uint8_t d5_gpio;
+    uint8_t d6_gpio;
+    uint8_t d7_gpio;
+    uint8_t card_detect;
+    uint8_t write_protect;
+    uint8_t card_int;
+    uint8_t width;
+} sdmmc_slot_info_t;
+
+/** pin and signal information of each slot */
+extern const sdmmc_slot_info_t sdmmc_slot_info[];
+
+#ifdef __cplusplus
+}
+#endif
+
+#endif /* _SOC_SDMMC_PERIPH_H_ */

docs/en/api-reference/peripherals/sd_pullup_requirements.rst

@@ -0,0 +1,153 @@
+SD Pullup Requirements
+======================
+
+CMD and DATA lines D0-D3 of the slave should be pulled up by 50KOhm resistor
+even in 1-bit mode or SPI mode. The pullups of the slave cards should be
+connected even if they're not connected to the host.
+
+The MTDI strapping pin is incompatible with DAT2 line pull-up by default
+when the code flash is 3.3V. See :ref:`mtdi_strapping_pin` below.
+
+Pullup inside Official Modules
+------------------------------
+
+For Espressif official modules, different weak pullups / pulldowns are
+connected to CMD, and DATA pins as below. To use these modules,
+these pins are required to be pulled up by 50KOhm resistors, since internal
+weak pullups are insufficient.
+
++-----------------------+-----+--------------------------+------+----------------------+------+
+| GPIO                  | 15  | 2                        | 4    | 12                   | 13   |
++=======================+=====+==========================+======+======================+======+
+| Name                  | CMD | DAT0                     | DAT1 | DAT2                 | DAT3 |
++-----------------------+-----+--------------------------+------+----------------------+------+
+| At startup            | WPU | WPD                      | WPD  | PU for 1.8v flash;   | WPU  |
+|                       |     |                          |      | WPD for 3.3v flash   |      |
++-----------------------+-----+--------------------------+------+----------------------+------+
+| Strapping requirement |     | Low to download to flash |      | High for 1.8v flash; |      |
+|                       |     |                          |      | Low for 3.3v flash   |      |
++-----------------------+-----+--------------------------+------+----------------------+------+
+
+- WPU: Weak pullup
+- WPD: Weak pulldown
+- PU: Pullup inside the module
+
+For Wrover modules, they use 1.8v flash, and have pullup on GPIO12 inside.
+For Wroom-32 Series, PICO-D4 modules, they use 3.3v flash, and is weakly
+pulled down internally. See :ref:`mtdi_strapping_pin` below.
+
+Pullup on Official Devkit (WroverKit)
+--------------------------------------
+
+For official Wrover Kit (till version 3), some of the pullups are provided on
+the board as the table below. For other devkits that don't have pullups,
+please connect them yourselves.
+
++-----------------------+-----+------+------+------+---------+
+| GPIO                  | 15  | 2    | 4    | 12   | 13      |
++=======================+=====+======+======+======+=========+
+| Name                  | CMD | DAT0 | DAT1 | DAT2 | DAT3    |
++-----------------------+-----+------+------+------+---------+
+| Pullup on the Kit     | PU  | PU   | PU   |      | PU & PD |
++-----------------------+-----+------+------+------+---------+
+
+- PU: Pullup
+- PD: Pulldown
+
+The DAT3 pullup conflicts with JTAG pulldown in WroverKit v3 and earlier, please
+either:
+
+1. pull it up by resistor less than 5KOhm (2kOhm suggested) in 4-bit mode.
+2. pull it up or drive it high by host or VDD3.3V in 1-bit mode.
+
+.. _mtdi_strapping_pin:
+
+MTDI strapping pin
+------------------
+
+MTDI (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:
+
+- For boards which don't use the internal regulator (VDD_SDIO) to power the
+  flash, GPIO12 can be pulled high.
+- For boards which use 1.8V flash chip, GPIO12 needs to be pulled high at
+  reset. This is fully compatible with SD card operation.
+- On boards which use the internal regulator and a 3.3V flash chip, GPIO12
+  must be low at reset. This is incompatible with SD card operation. Please
+  check the table below to see whether your modules/kits use 3.3v flash.
+
++-----------------+---------------+--------------------------------------+
+| Module          | Flash voltage | DAT2 connections                     |
++=================+===============+======================================+
+| PICO-D4         | 3.3V          | Internal PD, change EFUSE and pullup |
++-----------------+               + or disable DAT2 line*                +
+| Wroom-32 Series |               |                                      |
++-----------------+---------------+--------------------------------------+
+| Wrover          | 1.8V          | Internal PU, pullup suggested        |
++-----------------+---------------+--------------------------------------+
+
+Official devkits of different types and version mount different types of
+modules, please refer to the table below to see whether your devkit can
+support SDIO slave without steps above.
+
++--------------------------+-----------------+---------------+
+| Devkit                   | Module          | Flash voltage |
++==========================+=================+===============+
+| PICO Kit                 | PICO-D4         | 3.3V          |
++--------------------------+-----------------+ (see steps    +
+| DevKitC                  | Wroom-32 Series | below)        |
++--------------------------+                 +               +
+| WroverKit v2 and earlier |                 |               |
++--------------------------+-----------------+---------------+
+| WroverKit v3             | Wrover          | 1.8V          |
++--------------------------+-----------------+---------------+
+
+If your board requires internal regulator with 3.3v output, to make it
+compatible with SD pullup, you can either:
+
+  - **In the case using ESP32 host only**, external pullup can be omitted and an
+    internal pullup can be enabled using a ``gpio_pullup_en(GPIO_NUM_12);`` call.
+    Most SD cards work fine when an internal pullup on GPIO12 line is enabled.
+    Note that if ESP32 experiences a power-on reset while the SD card is
+    sending data, high level on GPIO12 can be latched into the bootstrapping
+    register, and ESP32 will enter a boot loop until external reset with
+    correct GPIO12 level is applied.
+  - **In the case using ESP32 slave in 1-bit mode**, speicfy
+    ``SDIO_SLAVE_FLAG_DAT2_DISABLED`` in the slave to avoid slave detecting on
+    DAT2 line. Note the host will not know 4-bit mode is not supported any more
+    by the standard CCCR register. You have to tell the host use 1-bit only.
+  - **For ESP32 host or slave**, another option is to burn the flash voltage
+    selection efuses. This will permanently select 3.3V output voltage for the
+    internal regulator, and GPIO12 will not be used as a bootstrapping pin.
+    Then it is safe to connect a pullup resistor to GPIO12. This option is
+    suggested for production use. NOTE this cannot be reverted once the EFUSE
+    is burnt.
+
+      The following command can be used to program flash voltage selection efuses **to 3.3V**:
+
+          components/esptool_py/esptool/espefuse.py set_flash_voltage 3.3V
+
+      This command will burn the `XPD_SDIO_TIEH`, `XPD_SDIO_FORCE`, and
+      `XPD_SDIO_REG` efuses. With all three burned to value 1, the internal
+      VDD_SDIO flash voltage regulator is permanently enabled at 3.3V. See
+      the technical reference manual for more details.
+
+      `espefuse.py` has a `--do-not-confirm` option if running from an automated flashing script.
+
+GPIO2 Strapping pin
+-------------------
+
+GPIO2 pin is used as a bootstrapping pin, and should be low to enter UART
+download mode. You may find it unable to enter the UART download mode if you
+correctly connect the pullup of SD on GPIO2. For WroverKit v3, there are
+dedicated circuits to pulldown the GPIO2 when downloading. For other boards,
+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.

docs/en/api-reference/peripherals/sdio_slave.rst

@@ -4,9 +4,6 @@ SDIO Card Slave Driver
 Overview
 --------
 
-.. note:: At the moment, this code has been proven to work on the Wrover-Kit V3. Earlier versions of the Wrover-Kit
-    and other development kits are electrically incompatible with this code. Functionality on other devboards is untested.
-
 The ESP32 SDIO Card peripherals (Host, Slave) shares two sets of pins as below table.
 The first set is usually occupied by SPI0 bus which is responsible for the SPI flash holding the code to run.
 This means SDIO slave driver can only runs on the second set of pins while SDIO host is not using it.
@@ -29,15 +26,33 @@ This means SDIO slave driver can only runs on the second set of pins while SDIO
 | DAT3     | 10    | 13    |
 +----------+-------+-------+
 
-The SDIO slave can run under 3 modes: SPI, 1-bit SD and 4-bit SD modes, which is detected automatically by the
-hardware. According to the SDIO specification, the host initialize the slave into SD mode by first sending CMD0 with
-DAT3 pin high, while initialize the slave into SPI mode by sending CMD0 with CS pin (the same pin as DAT3) low. After the
-initialization, the host can enable the 4-bit SD mode by writing CCCR register 0x07 by CMD52. All the bus detection
-process are handled by the slave peripheral.
+The SDIO slave can run under 3 modes: SPI, 1-bit SD and 4-bit SD modes, which
+is detected automatically by the hardware. According to the SDIO
+specification, CMD and DAT0-3 lines should be pulled up no matter in 1-bit,
+4-bit or SPI mode. Then the host initialize the slave into SD mode by first
+sending CMD0 with DAT3 pin high, while initialize the slave into SPI mode by
+sending CMD0 with CS pin (the same pin as DAT3) low.
+
+.. note:: CMD and DATA lines D0-D3 of the card should be pulled up by 50KOhm resistor
+  even in 1-bit mode or SPI mode. Most official devkits don't meet the pullup
+  requirements by default, and there are conflicts on strapping pins as well.
+  Please refer to :doc:`sd_pullup_requirements` to see how to setup your
+  system correctly.
+
+.. toctree::
+    :hidden:
+
+    sd_pullup_requirements
 
-The host has to communicate with the slave by an ESP-slave-specific protocol. The slave driver offers 3 services over
-Function 1 access by CMD52 and CMD53: (1) a sending FIFO and a receiving FIFO, (2) 52 8-bit R/W registers shared by
-host and slave, (3) 16 interrupt sources (8 from host to slave, and 8 from slave to host).
+After the initialization, the host can enable the 4-bit SD mode by writing
+CCCR register 0x07 by CMD52. All the bus detection process are handled by the
+slave peripheral.
+
+The host has to communicate with the slave by an ESP-slave-specific protocol.
+The slave driver offers 3 services over Function 1 access by CMD52 and CMD53:
+(1) a sending FIFO and a receiving FIFO, (2) 52 8-bit R/W registers shared by
+host and slave, (3) 16 interrupt sources (8 from host to slave, and 8 from
+slave to host).
 
 Terminology
 ^^^^^^^^^^^
@@ -215,6 +230,7 @@ There are several ways to use the ``arg`` in the queue parameter:
 
        More about this, see :example:`peripherals/sdio`.
 
+
 Application Example
 -------------------
 

docs/en/api-reference/peripherals/sdmmc_host.rst

@@ -60,6 +60,8 @@ See :doc:`SD/SDIO/MMC Driver <../storage/sdmmc>` for the higher level driver whi
 
 See :doc:`SD SPI Host Driver <sdspi_host>` for a similar driver which uses SPI controller and is limited to SPI mode of SD protocol.
 
+See :doc:`sd_pullup_requirements` for pullup support and compatiblities about modules and devkits.
+
 API Reference
 -------------
 

docs/zh_CN/api-reference/peripherals/sd_pullup_requirements.rst

@@ -0,0 +1 @@
+.. include:: ../../../en/api-reference/peripherals/sd_pullup_requirements.rst