HARDWARE INTERFACING

 ADC 0808 Interfacing with 8086 :

 

ADC means analog to digital converter ,which can convert analog voltage in to TTL (Transistor Transistor Logic) voltage level.

As shown in below IC 0808 interfacing:

                                                           fig.ADC 0808 interfacing

- Mainly ADC has three pins

i) SOC : start of conversion which can start conversion from analog voltage level to fix two digital voltage level

ii) Enable : Initially this pin should be High to Low then only conversion start.

iii) Output Enable : This pin is active high.

iv) EOC : End of conversion This pin shows the end of conversion means conversion is over.


How analog signal is Converted in to Digital signal ????????????

                                          fig. Analog to Digital Converter using Waveform 

As shown in above fig. the analog signal is converted in to digital signal by using
Sampling 

Quantization 

Encoding

                                                   fig.Graphical Representation of ADC

ALGORITHM :

0) START

i) Send control word of 8255 to initialize 8255 chip.
ii) Make CLK input high.
iii) send SOC.
iv) Check for EOC.
v) Read the output at PORT A.
vi) Stop.


OVER ALL HARDWARE SETUP OF ADC WITH MICRO PROCESSOR:

As shown in below hardware setup of ADC

fig. Over all hard ware set up of ADC interfacing

PROGRAM:

                                                        fig.program written in mini-com.


                 
          INPUT CONNECTION:
Case i)
For input Voltage = 2V
 

                                                         fig.Input connection of ADC 
Every power supply has two terminal
i) Positive (RED color)
ii) Negative (Black color)

These connection is given to ADC kit and with the help of RFC cable we connect ADC to Micro Processor kit.



OUTPUT CHECK ON MINI-COM :

For Analog Input 2v we get Digital Output 88H 

                                            fig.OUTPUT of ADC see on Mini-com

Case ii)
For input Voltage = 5V

                                                        fig.Input connection of ADC



OUTPUT CHECK ON MINI-COM :

For Analog Input 5v we get Digital Output FFH

                                                  fig.OUTPUT of ADC see on Mini-com