Specifications

dsPIC33F Family Reference Manual

Example 16-5: Code for Alternate Sampling Using DMA

/********************************************************************************************

* FileName: adcDrv1.c

* Dependencies: Header (.h) files if applicable, see below

* Processor: dsPIC33Fxxxx

* Compiler: MPLAB® C30 v2.01.00 or higher

* SOFTWARE LICENSE AGREEMENT:

* Microchip Technology Inc. (“Microchip”) licenses this software to you solely for use with

* Microchip dsPIC® digital signal controller products. The software is owned by Microchip

* *

* SOFTWARE IS PROVIDED “AS IS.” MICROCHIP EXPRESSLY DISCLAIMS ANY WARRANTY OF ANY KIND,

* WHETHER EXPRESS OR IMPLIED, INCLUDING BUT NOT LIMITED TO, THE IMPLIED WARRANTIES OF

* MERCHANTABILITY, FITNESS FOR A PARTICULAR PURPOSE, OR NON-INFRINGEMENT. IN NO EVENT

* SHALL MICROCHIP BE LIABLE FOR ANY INCIDENTAL, SPECIAL, INDIRECT OR CONSEQUENTIAL DAMAGES,

* LOST PROFITS OR LOST DATA, HARM TO YOUR EQUIPMENT, COST OF PROCUREMENT OF SUBSTITUTE GOODS,

* TECHNOLOGY OR SERVICES, ANY CLAIMS BY THIRD PARTIES (INCLUDING BUT NOT LIMITED TO

* ANY DEFENSE THEREOF), ANY CLAIMS FOR INDEMNITY OR CONTRIBUTION, OR OTHER SIMILAR COSTS.

*********************************************************************************************/

#if defined(__dsPIC33F__)

#include "p33fxxxx.h"

#elif defined(__PIC24H__)

#include "p24hxxxx.h"

#endif

#include "adcDrv1.h"

#include "tglPin.h"

// Define Message Buffer Length for ECAN1/ECAN2

#define MAX_CHNUM 5

// Highest Analog input number enabled for alternate sampling

#define SAMP_BUFF_SIZE 16 // Size of the input buffer per analog input

// Number of locations for ADC buffer = 2 (AN4 and AN5) x 16 = 32 words

// Align the buffer to 32words or 64 bytes. This is needed for peripheral indirect mode

int BufferA[MAX_CHNUM+1][SAMP_BUFF_SIZE] __attribute__((space(dma),aligned(64)));

int BufferB[MAX_CHNUM+1][SAMP_BUFF_SIZE] __attribute__((space(dma),aligned(64)));

void ProcessADCSamples(int * AdcBuffer);

/*=============================================================================

ADC Initialisation for Channel Scan

=============================================================================*/

void initAdc1(void)

{

AD1CON1bits.FORM = 3; // Data Output Format: Signed Fraction (Q15 format)

AD1CON1bits.SSRC = 2; // Sample Clock Source: GP Timer starts conversion

AD1CON1bits.ASAM = 1; //

ADC Sample Control: Sampling begins immediately after conversion

AD1CON1bits.AD12B = 0; // 10-bit ADC operation

AD1CON2bits.ALTS=1; // Alternate Input Sample Mode Select Bit

AD1CON2bits.CHPS = 0; // Converts CH0