Section 22. 12-bit High-Speed Successive …

1 2015-2016 Microchip Technology 22-1 Section 22. 12-bit High-Speed Successive approximation Register (SAR) analog -to- digital converter (ADC)This Section of the manual contains the following major Introduction .. Control registers .. ADC ADC Module Configuration .. Additional ADC Functions .. Interrupts .. Operation During Power-Saving Modes .. Effects of Transfer Function .. ADC Sampling Requirements .. Connection Considerations .. Related Application Revision History .. 22-120 PIC32 Family Reference ManualDS60001344B-page 22-2 Preliminary 2015-2016 Microchip Technology INTRODUCTIONThe PIC32 12-bit High-Speed Successive approximation Register (SAR) analog -to-DigitalConverter (ADC) includes the following features: 12-bit resolution Up to eight ADC modules with dedicated Sample and Hold (S&H) circuits (see Note 1) Two dedicated ADC modules can be combined in Turbo mode to provide double conversion rate Single-ended and/or differential inputs Can operate during Sleep mode Supports touch sense applications Up to six digital comparators Up to six digital filters supporting two modes.

2 - Oversampling mode- Averaging mode FIFO and DMA engine for dedicated ADC modules (see Note 2) Early interrupt generation resulting in faster processing of converted data Designed for motor control, power conversion, and general purpose applicationsThe dedicated ADC modules use a single input (or its alternate) and is intended for high -speedand precise sampling of time-sensitive or transient inputs, whereas the shared ADC moduleincorporates a multiplexer on the input to facilitate a larger group of inputs, with slower sampling,and provides flexible automated scanning option through the input scan each ADC module, the analog inputs are connected to the S&H capacitor.

3 The clock,sampling time, and output data resolution for each ADC module can be set independently. TheADC module performs the conversion of the input analog signal based on the configurations setin the registers . When conversion is complete, the final result is stored in the result buffer for thespecific analog input and is passed to the digital filter and digital comparator if configured to usedata from this particular simplified block diagram of the ADC module is illustrated in Figure :This family reference manual Section is meant to serve as a complement to devicedata sheets. Depending on the device, this manual Section may not apply to allPIC32 refer to the note at the beginning of the ADC chapter in the current devicedata sheet to check whether this document supports the device you are data sheets and family reference manual sections are available fordownload from the Microchip Worldwide Web site at: 1:Depending on the device, the 12-bit High-Speed SAR ADC has up to seven dedicated ADC modules and one shared ADC module.

4 Throughout this chapter, the diagrams and code examples refer to a device with seven dedicated ADC modules (ADC0-ADC6) and one shared ADC (ADC7). Please consult the ADC chapter in the specific device data sheet to determine which ADC modules are available for your :This feature is not available on all devices. Refer to the ADC chapter in the specific device data sheet to determine :Prior to enabling the ADC module, the user application must copy the ADC calibration data (DEVADCx) from the Configuration memory into the ADC Configuration registers (ADC0 CFG-ADC7 CFG). Refer to the ADC chapter in the specific device data sheet for more information. 2015-2016 Microchip Technology 22-3 Section 22.

5 12-bit High-Speed SAR ADCF igure 22-1:ADC Block Diagram Note:The number of ADC modules, analog inputs, ANa, ANb, ANc, and ANd, and the FIFO and DMA featuresare shown as an example. Refer to the ADC chapter in the specific device data sheet to determine theactual ANx selections, ADC module availability, and the specific FIFO and DMA +VREF-VREFSEL<2:0>VREFHVREFLADCSEL<1:0>CONCLKDIV<5:0>TCYFRCPBCLKTQADCDIV<6:0>(ADCxTIME<22:16>)ADCDIV<6:0>(ADCCON2<6:0>) (Dedicated ADC) (Dedicated ADC)FIFODMAD igital FilterDigital ComparatorInterrupt/EventCapacitive Voltage Divider (CVD)Interrupt/EventTriggers,Turbo Channel, Scan Control LogicTriggerStatus and Control RegistersADC6SH0 ALT<1:0>(ADCTRGMODE<17:16>)ANxVREFL01 DIFFx<1>(ADCIMCONx<x>)ANaAN1 VREFL01 DIFF1<1>(ADCIMCON1<3>)SH6 ALT<1:0>(ADCTRGMODE<29.)

6 28>)ANxVREFL01 DIFFx<1>(ADCIMCONx<x>)AN49 IVCTMUIVBATAN48AN7 CVD CapacitorTCLKANbANcANd00011011 ANbANcANd00011011 SYSTEM BUSANaInterruptDataPIC32 Family Reference ManualDS60001344B-page 22-4 Preliminary 2015-2016 Microchip Technology 22-2:FIFO Block DiagramFEN(ADCFSTAT<31>FIFO(Depth Device Dependent)ADCFIFODATA<31:0>ADCID<2:0>ADCFSTAT<2:0>ADCx IDADCx IDConverted DataADC6 ADC6EN(ADCFSTAT<30>)ADC5 ADC5EN(ADCFSTAT<29>)ADC0 ADC0EN(ADCFSTAT<24>)If data available in FIFOFRDYADCFSTAT<22>FIEN(ADCFSTAT<23>InterruptFCNT<7:0>ADCFSTAT<15:8>(Number of data in FIFO)Note:The number of ADC modules, analog inputs, ANa, ANb, ANc, and ANd, and the FIFO and DMA featuresare shown as an example. Refer to the ADC chapter in the specific device data sheet to determine theactual ANx selections, ADC module availability, and the specific FIFO and DMA features.)

7 2015-2016 Microchip Technology 22-5 Section 22. 12-bit High-Speed SAR ADCF igure 22-3:DMA Block DiagramDMAGEN(ADCDMASTAT<31>)ADC6 DMAEN(ADC6 TIME<23>)ADC5 ADC0 DMAEN(ADC5 TIME<23>)DMAEN(ADC0 TIME<23>)Buffer A (ADC0)Buffer B (ADC0)Buffer A (ADC1)Buffer B (ADC1)Buffer A (ADC6)Buffer B (ADC6)2 DMABL<2:0>2 DMABL<2:0>2 DMABL<2:0>BufferFull?RAF0(ADCDMASTAT<0>)RAFIEN0(ADCDMASTAT<8>)InterruptBufferFull?RBF6(ADCDMASTAT<22>)RBFIEN6(ADCDMASTAT<30>)InterruptData Count for Buffer-A (ADC0)Data Count for Buffer-B (ADC0)Data Count for Buffer-A (ADC1)Data Count for Buffer-B (ADC1)Data Count for Buffer-A (ADC6)Data Count for Buffer-B (ADC6)DMABADDR<31:0>CNTBADDR<31:0>CNTBADDR<31:0> + 1 CNTBADDR<31:0> + 2 CNTBADDR<31:0> + 3 Note:The number of ADC modules, analog inputs, ANa, ANb, ANc, and ANd, and the FIFO and DMA featuresare shown as an example.

8 Refer to the ADC chapter in the specific device data sheet to determine theactual ANx selections, ADC module availability, and the specific FIFO and DMA Family Reference ManualDS60001344B-page 22-6 Preliminary 2015-2016 Microchip Technology CONTROL REGISTERSThe PIC32 12-bit High-Speed SAR ADC module has the following Special Function registers (SFRs): ADCCON1: ADC Control Register 1 This register controls the basic operation of all ADC modules, including behavior in Sleepand Idle modes, and data formatting. This register also specifies the vector shift amounts forthe Interrupt Controller. Additional ADCCON1 functions include controlling the Turbo featureof the ADC, the RAM buffer length in DMA mode, and Capacitive Voltage Division (CVD).

9 ADCCON2: ADC Control Register 2 This register controls the reference selection for all ADC modules, the sample time for theshared ADC module, interrupt enable for reference, early interrupt selection, and clockdivision selection for the shared ADC. ADCCON3: ADC Control Register 3 This register enables ADC clock selection, enables/disables the digital feature for thededicated and shared ADC modules and controls the manual (software) sampling andconversion. ADCTRGMODE: ADC Triggering Mode for Dedicated ADC RegisterThis register has selections for alternate analog inputs and includes trigger settings for thededicated ADC modules. ADCIMCON1: ADC Input Mode Control Register 1 through ADCIMCON4: ADC Input Mode Control Register 4 These registers enable the user to select between single-ended and differential operationas well as select between signed and unsigned data format.

10 ADCGIRQEN1: ADC Global Interrupt Enable Register 1 andADCGIRQEN2: ADC Global Interrupt Enable Register 2 These registers specify which of the individual input conversion interrupts can generate theglobal ADC interrupt. ADCCSS1: ADC Common Scan Select Register 1 andADCCSS2: ADC Common Scan Select Register 2 These registers specify the analog inputs to be scanned by the common scan trigger. ADCDSTAT1: ADC Data Ready Status Register 1 and ADCDSTAT2: ADC Data Ready Status Register 2 These registers contain the interrupt status of the individual analog input conversions. Eachbit represents the data-ready status for its associated conversion result. ADCCMPENx: ADC digital Comparator x Enable Register ( x = 1 through 6)These registers select which analog input conversion results will be processed by the digitalcomparator.