1. ECT 357 Ch 10 Analog to Digital COnversion

2. Today’s Quote: It’s better to die with a good name than to live with a bad one. It’s better to die with a good name than to live with a bad one. A good name is better than precious ointment. A good name is better than precious ointment. Ecclesiastes 7:1 Ecclesiastes 7:1

3. Analog to Digital Converter Types Sigma Delta Sigma Delta Incremental Incremental Successive Approximation Successive Approximation Flash Flash

4. PIC18F452 ADC Overview 10 bit resolution 10 bit resolution 2 output formats (ADRESH,ADRESL) 2 output formats (ADRESH,ADRESL) 15 port configurations 15 port configurations Internal/external reference Internal/external reference Interrupt option Interrupt option Clock options Clock options

5. ADC Uses Analog Input Analog Input Control Loops Control Loops PID Control PID Control External Interfaces External Interfaces

6. ADC I/O pins Port A 0-3, Port A 5, Port E 0-2 Port A 0-3, Port A 5, Port E 0-2 Port Configuration determined by PCFG bits in ADCON1 Port Configuration determined by PCFG bits in ADCON1 Selects internal or external voltage reference Selects internal or external voltage reference Selects digital input or analog input for each pin Selects digital input or analog input for each pin

7. ADC Characteristics ADC conversion time (50kHz<X<625kHz) ADC conversion time (50kHz<X<625kHz) Minimum sample time (15 usec) Minimum sample time (15 usec) Conversion time (12xADC clock period) Conversion time (12xADC clock period)

8. ADC Initialization and Operation Setup ADCON0 Setup ADCON0 Setup ADCON1 Setup ADCON1 Select Channel Select Channel Wait 15 usec for holding cap Wait 15 usec for holding cap Set GO_DONE bit in ADCON0 Set GO_DONE bit in ADCON0 Wait for GO_DONE to clear Wait for GO_DONE to clear Get data out of ADRESH and ADRESL Get data out of ADRESH and ADRESL