Micro SD card mini TF module for arduino, reader, SPI interfaces with level converter chip
Module Features
1. Support Micro SD card, Micro SDHC card (high speed card)
2. Built-in level change circuit, that is, the interface level can be 5V or 3.3V
3. The power supply is 4.5V ~ 5.5V, integrated regulator circuit of 3.3V
4. The Communication interface is a standard SPI interface
5. 4 M2 screw positioning holes for easy installation
interface
A total of 6 pins (GND, VCC, MISO, MOSI, SCK, CS), GND is ground, VCC is power, MISO, MOSI, SCK is SPI bus, CS is signal pin chip selection.
3.3V Voltage Regulator Circuit
The 3.3V of LDO regulated output is the level converter chip and Micro SD card.
Circuit level change
The signal to the direction of the Micro SD card is converted to 3.3V, and the MISO signal from the Micro SD card to the control interface is also converted to 3.3V. Usually the AVR microcontroller system can read the signal.
Micro SD bridge
It is a self-elastic card holder for easy insertion and removal of cards.
Positioning hole
4 M2 screw positioning holes with a hole diameter of 2.2mm, which makes the module easy to install and position, and realize the combination of modules

SD card reader pins
The GND terminal is connected to 0 Volts (ground).
The VCC terminal is connected to 5 Volts.
Meaning of the other terminals:
MISO: Master In, Slave Out. Other abbreviations: SDI, DI, SI
MOSI: Master Out, Slave In. Other abbreviations: SDO, SDA, DO, SO
SCK Serial ClocK. Other abbreviations: SCLK, SCL
CS Chip Select. Other abbreviations: SS (Slave Select), nCS, CS, nSS, STE, CSN
In the case of the SDI/SDO naming convention, the SDO of the master must be connected to the SDI of the slave and vice versa.
To avoid confusion when wiring, it is therefore often recommended to use MISO-MOSI names which avoid some ambiguity.