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esp32/machine_sdcard: Add SDCard SPI mode support for ESP32-S2,C3,C6.

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These micros don't have full SDMMC host support, but they can initialise
the SDCard in SPI mode.

A bit limited on C3 and C6 as they only have one host SPI peripheral.

This work was funded through GitHub Sponsors.

Signed-off-by: Angus Gratton <angus@redyak.com.au>
This commit is contained in:
Angus Gratton
2025-02-05 15:17:27 +11:00
committed by Damien George
parent 79fb5aa878
commit c85eefc55b
2 changed files with 119 additions and 41 deletions
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56
docs/library/machine.SDCard.rst
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@@ -77,24 +77,34 @@ ESP32
`````
SD cards support access in both SD/MMC mode and the simpler (but slower) SPI
mode. ESP32 and ESP32-S3 chips can access SD cards using either mode. SPI mode
makes use of a `SPI` host peripheral, which cannot concurrently be used for
something else.
mode.
SPI mode makes use of a `SPI` host peripheral, which cannot concurrently be used
for other SPI interactions.
The ``slot`` argument determines which mode is used. Different values are
available on different chips:
supported on different chips:
====== ================= ============ ========================
Slot Supported chips Mode Supported data width
====== ================= ============ ========================
0 ESP32-S3 SD/MMC 1, 4, or 8 bits.
1 ESP32, ESP32-S3 SD/MMC 1 or 4 bits.
2 ESP32, ESP32-S3 `SPI` (id=1) 1 bit.
3 ESP32, ESP32-S3 `SPI` (id=0) 1 bit.
====== ================= ============ ========================
========== ======== ======== ============ ============
Chip Slot 0 Slot 1 Slot 2 Slot 3
========== ======== ======== ============ ============
ESP32 SD/MMC SPI (id=1) SPI (id=0)
ESP32-C3 SPI (id=0)
ESP32-C6 SPI (id=0)
ESP32-S2 SPI (id=1) SPI (id=0)
ESP32-S3 SD/MMC SD/MMC SPI (id=1) SPI (id=0)
========== ======== ======== ============ ============
.. note:: On the original ESP32, SDMMC slot 0 is unavailable as its pins are
used to communicate with on-board flash memory.
Different slots support different data bus widths (number of data pins):
========== ========== =====================
Slot Type Supported data widths
========== ========== =====================
0 SD/MMC 1, 4, 8
1 SD/MMC 1, 4
2 SPI 1
3 SPI 1
========== ========== =====================
.. note:: Most ESP32 modules that provide an SD card slot using the
dedicated hardware only wire up 1 data pin, so the default
@@ -105,8 +115,9 @@ Additional details depend on which ESP32 family chip is in use:
Original ESP32
~~~~~~~~~~~~~~
Pin assignments in SD/MMC mode are fixed on the original ESP32. When accessing a
card in SPI mode, pins can be set to different values in the constructor.
In SD/MMC mode (slot 1), pin assignments in SD/MMC mode are fixed on the
original ESP32. The SPI mode slots (2 & 3) allow pins to be set to different
values in the constructor.
The default pin assignments are as follows:
@@ -177,6 +188,19 @@ parameters ``sck``, ``cs``, ``miso``, ``mosi`` as needed to assign pins.
In either mode the ``cd`` and ``wp`` pins default to disabled, unless set in the
constructor.
Other ESP32 chips
~~~~~~~~~~~~~~~~~
Other ESP32 family chips do not have hardware SD/MMC host controllers and can
only access SD cards in SPI mode.
To access a card in SPI mode, set ``slot`` parameter value 2 or 3 and pass
parameters ``sck``, ``cs``, ``miso``, ``mosi`` to assign pins.
.. note:: ESP32-C3 and ESP32-C6 only have one available `SPI` bus, so the only
valid ``slot`` parameter value is 2. Using this bus for the SD card
will prevent also using it for :class:`machine.SPI`.
cc3200
``````