Successfully reported this slideshow.
We use your LinkedIn profile and activity data to personalize ads and to show you more relevant ads. You can change your ad preferences anytime.

Interfacing adc


Published on

Published in: Technology
  • Be the first to comment

Interfacing adc

  1. 1. Interfacing ADC
  2. 2. What is ADC? <ul><li>ADC – analog to digital conversion </li></ul><ul><li>It converts the given analog value to a digital value </li></ul><ul><li>There are lot of digital ICs available to convert analog to digital </li></ul><ul><li>In microcontroller interfacing the frequently used ICs are 0804 and 0808 </li></ul>
  3. 3. 0804 – an ADC
  4. 4. Interfacing ADC
  5. 5. Working of ADC <ul><li>For every interfacing initialization is needed, </li></ul><ul><li>For ADC the initial values are </li></ul><ul><ul><ul><li>INTR=1; // interrupt for completion of ADC process </li></ul></ul></ul><ul><ul><ul><li>rd=1; // read from 0804 </li></ul></ul></ul><ul><ul><ul><li>wr=1; // start conversion write.. </li></ul></ul></ul>
  6. 6. Working of ADC contd. <ul><li>Next step is to start the process of converting analog voltage to digital data </li></ul><ul><li>By changing the state of the write pin – a transition from 0 to 1 will start the conversion. </li></ul><ul><li>End of conversion will be acknowledged by a change in the INTR state… </li></ul><ul><li>See the timing diagram of the conversion starts </li></ul>
  7. 7. Timing diagram of START Conv.
  8. 8. Reading the data <ul><li>To read the data from 0804 the read pin state must be ‘0’. </li></ul><ul><li>After reading the data read pin must be change back into ‘1’ </li></ul><ul><li>The data obtained from the 0804 will be from ‘0’ to ‘255’ , since the ADC is a 8 bit adc and obtained value will be inbetween 2 0 to 2 8 . </li></ul>
  9. 9. Timing diagram of reading from 0804
  10. 10. Assignment <ul><li>Convert analog and display in LCD </li></ul><ul><li>Find the room temperature and display the degree Celsius value in LCD. </li></ul>