低功耗、四路、12位、电压输出DAC，串行接口 max525的avr驱动程序-Low-power, four-way, 12-bit, voltage output DAC, serial interface max525 driver of avr

8到3译码器 74HC138是一款高速CMOS器件，74HC138引脚兼容低功耗肖特基TTL（LSTTL）系列。 74HC138译码器可接受3位二进制加权地址输入（A0, A1和A2），-8-3 decoder 74HC138 is a high-speed CMOS, 74HC138 pin compatible with low power Schottky TTL (LSTTL) series. 74HC138 decoder accepts three binary weighted a