MAX7219和PS721 9分别由美国MAXIM 能上，PS721 9 可以完全兼容公司和武汉力源公司设计生产，它们均采用流行的同步串行外设接口(SPI)，可以与任何一种单片机方便接口 -MAX7219 and PS721 9 by MAXIM to the United States, PS721 9 can be completely compatible with the company and Wuhan Liyuan design and production company,

SPI是串行传送口，所传文件是用来驱动SPI接口的函数，-SPI is a serial transmission interface, the file transfer is used to drive the SPI interface functions,