NIOS II 的几个源代码，读SD卡、直流电机的转速调节、简易数字示波器、简易频谱分析仪、USB文本阅读器,NIOS II several source code, read SD cards, the speed regulation of DC motor, simple digital oscilloscope, spectrum analyzer summary, USB version of Reader

读SD卡，主要涉及SOPC技术，NIOS软核编程，供学习参考用-Reading SD card, mainly related to SOPC technology, NIOS soft-core programming for the study and reference