STM32版本Arduino读写SD卡程序，支持2G~32G，64G的卡也能读写32G，对SD卡没要求，SD卡部分的电路越简单越好，程序里面已经注明引脚接法。(STM32 version Arduino read and write SD card program to support 2G ~ 32G, 64G card can read and write 32G, SD card does not require, SD card part of the circuit as simple as possible, the program has been marked pin connection.)