本文档内是基于Verilog HDL的SD卡SPI模式下的读写程序，内有详细的注释，且通俗易懂。-This document is based on Verilog HDL in the SD card in SPI mode to read and write procedures, which are detailed notes, and easy to understand.

基于LATEX进行标准化降水指数编辑文档的计算程序，主要用于干旱分级的确定指数。(Based on LATEX, standardized precipitation index SPI calculation program is mainly used for the determination index of drought classification.)

以LATEX为基础，采用标准化的降水指数综合计算程序，主要用于干旱分类的确定指标。(Based on LATEX, standardized precipitation index SPI calculation program is mainly used for the determination index of drought classification.)