sd卡官方资料，SD卡（Secure Digital Memory Card）是一种为满足安全性、容量、性能和使用环境等各方面的需求而设计的一种新型存储器件，SD卡允许在两种模式下工作，即SD模式和SPI模式，本 系统采用SPI模式。-Official data sd card, SD card (Secure Digital Memory Card) is to meet the security, capacity, performance and use of environmental and other needs and design a new type of memory devices, SD cards allow the two modes that SD mode and SPI mode, the system uses SPI mode.