说明：  sdramtest.c：一个很全面的测试源代码，包括读写测试，数据线测试，地址线测试等 sdram数据线和地址线短路测试原理 内存及闪存IC测试原理 一共三个文件，比较全面的介绍了。
(sdramtest.c: a very comprehensive test source code, including reading and writing test, test of the data lines, address lines test sdram data and address lines of the principle of the short-circuit test memory and flash memory IC test principle a total of three files, more comprehensive introduction .)