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