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A/D Conversion with PIC 16F877

Dr. Charles Kim

Department of Electrical and Computer Engineering

Howard University

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A/D Conversion Port

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ADC Related Registers

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Registers

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ADCON0

11001001

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ADCON1

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AD Result Justification

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Resolution (10bit and 8bit)

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PIE1 and PIR1 Registers

Disable this flag in initialization

This bit is set when conversion is done. So we have to clear it for the next conversion.

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ADC Diagram and Conversion Process

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AD Procedure� INITIALIZATION� 1. Configure the A/D module:

� Configure analog pins / voltage reference /and digital I/O (ADCON1)� Select A/D input channel (ADCON0)� Select A/D conversion clock (ADCON0)� Turn on A/D module (ADCON0)

� 2. Configure A/D interrupt (DISABLE IT):PIE1 register� Clear ADIE bit

� CONVERSION� 1. Wait the required acquisition time.� 2. Start conversion

� Set GO/DONE bit (ADCON0)� 3. Wait for A/D conversion to complete

� Polling for the GO/DONE bit to be cleared� 4. Clear Conversion Complete Flag: PIR1 register

� Clear ADIF bit� 5. Read A/D Result register pair (ADRESH:ADRESL).

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Rheostat Connection to AN0

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Coding – initialization

Movlw 0xC9

For RA1

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Coding – ADC subroutine

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Printing the Result on PC screen –using the upper 8-bit only

0V

5V

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Continued

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Continued-

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Continued- (subroutine TEN)

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10-bit results with 3 decimal points

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Continued

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Continued

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Infrared Ranger Application

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Sharp Ranger Module

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GP2D12 – Non-linearity

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GP2D12D Connection to AN1

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GP2D12D Coding – ADC

11010001

For RA2

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GP2D12D coding – Distance Conversion

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CSA-1V Hall Effect Current Sensor

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Sensitivity

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ADC for CSA1V

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Pseudo-Code for CSA-1V

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Battery (power) Monitor using MAX471/MAX472

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Connection Diagram for Battery Monitoring

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Allegro ACS750 Current Sensor

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Current vs. Output Voltage

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Connection and Coding

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Thermister for Temperature Sensing