常用芯片手册 硬件开发常用的芯片手册,包括74HC00,74HC02,74HC03,74HC04,74HC05,74HC08,74HC11,74HC14,74HC20,74HC27,74HC30,74HC32,74HC34,74HC42,74HC51,74HC58,74HC73,74HC74A,74HC75,74