1. Control Interface: Six pins (GND, VCC, MISO, MOSI, SCK, CS), GND to ground, VCC is power supply, MISO, MOSI, SCK is SPI bus, CS is chip selecting signal pin2. 3.3V voltage regulator circuit: LDO regulator output 3.3V3. Level conversion circuit: signal of Micro SD card direction into 3.3V, MISO signal which controls interface direction is also converted to 3.3V. general AVR microcontroller system can read the signal;4. Micro SD card connector: self-spring socket, easy to insertion and removal card5. Positioning holes: 4pcs 2mm diameter M2 screws hole, good for installing positioning, to achieve inter-module combination