SDMMC Protocol Layer Driver

SD Host Side Related Component Architecture

Architecture Graph

                        ┌─────────────────────────────────────────────┐
                        │                                             │
                        │  SD Protocol Layer Driver: components/sdmmc │
                        │                                             │
                        └──────────▲────────────────────▲─────────────┘
                                   │                    │
                                   │                    │
                        Implements │                    │ Implements
                                   │                    │
┌──────────────────────────────────┴─────┐         ┌────┴───────────────────────────────────┐
│                                        │         │                                        │
│Host Driver: components/esp_driver_sdmmc│         │Host Driver: components/esp_driver_sdspi│
│                                        │         │                                        │
└────────────────────────────────────────┘         └────────────────────────────────────────┘

Components

• sdmmc: SD protocol layer driver, it provides SD protocol related definitions and interfaces. With corresponding implementation drivers, sdmmc APIs can help you:
  • send commands to slave devices
  • send and receive data
  • handle error conditions within the bus
• esp_driver_sdmmc: SDMMC Host driver for ESP SDMMC hardware, it implements the sdmmc protocol interfaces.
• esp_driver_sdspi: SDSPI Host driver for ESP GPSPI hardware, it implements the sdmmc protocol interfaces.

Dependency

• esp_driver_sdmmc is in driver layer (G2), it relies on sdmmc
• esp_driver_sdspi is in driver layer (G2), it relies on sdmmc
• sdmmc does not and should not rely on esp_driver_sdmmc or esp_driver_sdspi. Though sdmmc is independent, it still stays in G2.

Configuration Options

CONFIG_SD_ENABLE_SDIO_SUPPORT

This configuration option allows you to enable/disable SDIO support. By default this option is enabled. Consider disabling SDIO support (CONFIG_SD_ENABLE_SDIO_SUPPORT=n) when card is Memory-only card and not when Combo cards which provide both I/O functionality and memory storage.