Mount an SD card reader
published: 28 January 2024 / updated 28 January 2024
Feeling cramped with the SPIFFS file system? So mount an SD card reader and benefit from storage space measured in gigagbytes!
The SD card reader
The choice fell on an SD card reader model with SPI interface. This model allows you to take out the SD card to read it on your computer.
All other models of SPI card readers may be suitable, provided they have the SPI interface.
Connecting the SPI card reader
The first operation consists of locating the four pins of the SPI port of your ESP3 card. These pins must be marked by the indication VSPI_ followed by the use of the pin: VPSI_MOSI, VSPI_MISO, VSPI_CLK and VSPI_CSI.On the ESP32-Wroom-32 card, correspondence of these pins:
--- ESP 32 --- --- SD Card --- G23 VSPI_MOSI <--> MOSI G19 VSPI_MISO MISO G18 VSPI_CLK SCK G05 VSPI_CS0 CS
The position of the pins may differ depending on the ESP32 card model.
This SD card reader is powered by 5V. It incorporates a regulator which reduces the voltage used at 3.3V.
Access to SD card contents
The first operation is to mount the SD card:
SD \ access SD vocabulary SD.begin \ mount SD card. Stack 1 if success, 0 if error
And that's it!
Finally. Almost...
Let's see a simple example. Let's start by seeing the files present on this SD card:
ls /sd \ display:
System Volume Information
oledTest.jpg
regSensSar.jpg
techRef01.jpg
Here, we find the three files previously recorded from a computer on this SD card.
Let's save a new file:
RECORDFILE /sd/config.fs \ define numbers of 74HC595 shift registers 3 constant NB_SHIFT_REGS
This saves a new file to our SD card, named config.fs.
In conclusion, this SD card reader opens up extraordinary development prospects.
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