A/D Converter andA/D Converter and
ComparatorComparator
PIC 12F675PIC 12F675
Zdeněk Matěj
72963@mail.muni.cz
A/D ConverterA/D Converter
►►Conversion of an analog input signal to a 10Conversion of an analog input signal to a 10--
bit binary representation of that signalbit binary representation of that signal
►►PIC 12F675 has 4 ADC (multiplexed)PIC 12F675 has 4 ADC (multiplexed)
►►Generates interrupt (ADIF)Generates interrupt (ADIF)
A/D block diagramA/D block diagram
A/DA/D -- ANSELANSEL
A/DA/D –– ADCON0ADCON0
A/DA/D –– output registersoutput registers
A/DA/D –– example (without INT)example (without INT)
//A/D//A/D initinit
//ADCS2 ADCS1 ADCS0 ANS3 ANS2 ANS1 ANS0//ADCS2 ADCS1 ADCS0 ANS3 ANS2 ANS1 ANS0
ANSEL=0b1100001;ANSEL=0b1100001;
//ADFM VCFG//ADFM VCFG —— —— CHS1 CHS0CHS1 CHS0 GO/DONE ADONGO/DONE ADON
ADCON0=0b00000000;ADCON0=0b00000000;
ADON=1; //ENABLE A/DADON=1; //ENABLE A/D convertorconvertor
GODONE=1;GODONE=1; //start//start
if (GODONE==0) {data=ADRESH;}if (GODONE==0) {data=ADRESH;} //data//data rdyrdy
ComparatorComparator
►►The PIC12F629/675 devices have one analogThe PIC12F629/675 devices have one analog
comparatorcomparator
►►Compare two analog valuesCompare two analog values
►►On GP0 and GP1 are inputs to theOn GP0 and GP1 are inputs to the
comparatorcomparator
►►GP2 can be the comparator outputGP2 can be the comparator output
►►Generates interrupt (CMIF)Generates interrupt (CMIF)
ComparatorComparator -- CMCONCMCON
ComparatorComparator –– operation modesoperation modes
ComparatorComparator –– voltage referencevoltage reference
►►The voltage reference can output 32 distinctThe voltage reference can output 32 distinct
voltage levelsvoltage levels
ComparatorComparator –– voltage referencevoltage reference
ComparatorComparator -- exampleexample
//init//init
//// -- COUTCOUT -- CINV CIS CM2 CM1 CM0CINV CIS CM2 CM1 CM0
CMCON=0;CMCON=0;
output=COUT;output=COUT;
ReferencesReferences
Source:Source:
http://ww1.http://ww1.microchipmicrochip..comcom//downloadsdownloads/en//en/devdeviicedoccedoc/41190c./41190c.pdfpdf