80C535 hardware/assembler course (2):

The analogue-to-digital converter contained in the 80C535 microcontroller is a complex unit. The structure is given in this article. The operation of the ADC is controlled via two special registers. The primary control register is located at address OD8H, and is called ADCON. Bits 0, 1 and 2 in this register control the multiplexer connected ahead of the A-D converter proper. These bits determine which input line on port P6 is connected to the ADC input for the next conversion cycle. The ADC mode is controlIed by bit 3 in the ADCON regrster. lf the bit is set to 0. the ADC stops after each conversion. If the bit is set to 1, the ADC operates continuously.