Related area

SD SPI

Hardware specification

ESP32

Is your feature request related to a problem?

By default, ESP-IDF does not provide a default 10MHz SDMMC speed, even though there is a note about it in sdmmc_common.c. This means that using SD SPI with SD cards that do not support the 20MHz default speed requires additional steps and code modification to initialize.

/* Find highest frequency in the following list,
     * which is below card->max_freq_khz.
     */
    const uint32_t freq_values[] = {
            SDMMC_FREQ_52M,
            SDMMC_FREQ_HIGHSPEED,
            SDMMC_FREQ_26M,
            SDMMC_FREQ_DEFAULT,
            //NOTE: in sdspi mode, 20MHz may not work. in that case, add 10MHz here.
    };

Describe the solution you'd like

Please add a default SDMMC_FREQ_10M definition to sdmmc_types.h and add it to freq_values in sdmmc_common.c.

Describe alternatives you've considered

No response

Additional context

No response

I have checked existing list of Feature requests and the Contribution Guide

• I confirm I have checked existing list of Feature requests and Contribution Guide.