这是经过验证可用的ADC代码,具有很高的参考值.
* Basic A2D sample code for an PIC16F87x device.
* This code willl set up the A2D module to return an
* 8-Bit result. If greater precision is needed, a 10-Bit
* result can be returned if read_a2d() is modified to
* return the short ((ADRESH<<8)+(ADRESL)). Note also that
* ADCON1 should be set to 0x80 in the init_a2d() routine
* instead of zero.