The two rows of pins can be welded on the top or on the bottom or not welded. The pins and the board are shipped together in three ways for customers to choose freely. The default delivery pins are installed on the front (as shown in the figure). The two pins are installed on the top by default. The pins are welded upward and can be led out with DuPont wires for extended experiments; the pins are welded downward and can be directly inserted into the perforated board or the PCB made by yourself, becoming part of the system. +5V, 3.3V and GND are all led out with 2.54 spacing pins, which is convenient for users to use ordinary DuPont wires for extended experiments. If DuPont wires are needed, we also sell them in our store. The C8051F chip has its own internal clock. All experiments are completed through the internal crystal oscillator. The board also reserves an external crystal oscillator. The development board has been tested to read and write SD cards. MiniSD memory cards of 2G and below can be recognized. Cards of 4G and above may not be recognized because they have not been tested yet. If the user has the ability, he can also improve the software to achieve better functions. New C8051F340 development board, compact component layout and standardized circuit routing. Two LEDs and two buttons on board. A standard DB9 serial port (female port). A miniSD card holder. Three power supply methods: USB power supply, external 5V power supply, and emulator power supply for the development board. It can be used as a learning board or as a core board directly in the project to improve efficiency. Note:Due to different production batches, the color of the base plate is sent randomly and cannot be specified, which will not affect the use. Colour:Blue Material:Plastic Package Contents: 1 * C8051F340 Microcontroller Development Board Only the above package content, other products are not included. Note: Light reflection and different displays may cause the color of the item in the picture a little different from the real thing. The measurement allowed error is +/- 1-3cm.