#ifndef ADCUTIL_H

#define ADCUTIL_H

#define ADC_VREF_MV 3300.0 //ADC reference volatage in miliVolts

double adc_to_mv(double adc){

return adc * ADC_VREF_MV / 1023.0f;

}

#define BATTERY_VOLTS (adc_to_mv(adcAvg[6]) * 11.0 / 1000.0) //Battery input uses a voltage divider of 11 (33K + 3.3K resistors)

#define DMA_SEG_COUNT 7 //Number of segments in DMA buffer (one for each channel)

#define DMA_SEG_LEN 16 //Lenght of each segments in words (number of samples per channel, stored in DMA buffer at one time)

#define DMA_TOTAL_LEN (DMA_SEG_COUNT*DMA_SEG_LEN) //=112 Total length of DMA buffer

unsigned int adcDmaA[DMA_SEG_COUNT][DMA_SEG_LEN] __attribute__((space(dma),aligned(256))); //IMPORTANT: align data to a power of 2 >= DMA_TOTAL_LEN*2

unsigned int adcDmaB[DMA_SEG_COUNT][DMA_SEG_LEN] __attribute__((space(dma),aligned(256))); //see http://ww1.microchip.com/downloads/en/DeviceDoc/70182b.pdf, page 22-31

#if 256 < DMA_TOTAL_LEN * 2

#error "Update aligned(..) above"; //memo if DMA_TOTAL_LEN changes

unsigned long adc_new_data();

void adc_init(){

//ADC MANUAL: http://ww1.microchip.com/downloads/en/DeviceDoc/70183C.pdf

AD1PCFGL = 0b1111111110000000; //Configure ports AN0..AN6 as analog, all others as digital (on POR all ports are analog by default)

AD1CSSL = 0b0000000001111111; //set inputs to be scanned AN0..AN6

AD1CON1 = 0; //defaults (see datasheet)

AD1CON1bits.SSRC =0b111;//Auto Convert

AD1CON1bits.ASAM = 1; //Auto-sample after each conversion

AD1CON2 = 0; //defaults (see datasheet),

AD1CON2bits.CSCNA = 1; //scan mode

AD1CON2bits.SMPI = DMA_SEG_COUNT -1; //6 segments in DMA buffer

AD1CON3 = 0; //defaults (see datasheet)

#define ADCS_PARAM 60 -1

AD1CON3bits.ADCS =ADCS_PARAM; //Tad = (ADCS<5:0> + 1) * Tcy = (ADCS + 1) / Fcy = 60 / 40Mhz = 1.5uS (min required Tad is 76nS for 10-bit mode)

#define SAMC_PARAM 30

AD1CON3bits.SAMC = SAMC_PARAM; //sample time = SAMC<4:0> * Tad = 30 * 1.5uS = 45 uS

//Total sample+conversion time per chanel = 12(conversion) + 30(sample) = 42Tad * 1.5us = 63uS

#define DMA_INTERVAL_US (63 * DMA_TOTAL_LEN) // = 63 * 112 = 7056 us , this should be integer, otherwise use conversion to integer

#if ADCS_PARAM != 60 -1 || SAMC_PARAM != 30 || DMA_SEG_COUNT != 7 || DMA_SEG_LEN !=16

#error "Update DMA_INTERVAL_US above"

#endif

AD1CON4bits.DMABL=0b100;//DMA buffer has 2^DMABL = 16 words per channel (per segment),

#if 16 != DMA_SEG_LEN

#error "Update AD1CON4 above"; //memo if DMA_SEG_LEN changes

#endif

AD1CHS0 = 0; //defaults (see datasheet)

AD1CHS123= 0; //defaults (see datasheet)

//Setup DMA buffer for ADC

//See: http://ww1.microchip.com/downloads/en/DeviceDoc/70182b.pdf

//Also sample: http://ww1.microchip.com/downloads/en/DeviceDoc/70183A.pdf, page 16-56

DMA0CONbits.AMODE =0b10; // Configure DMA for Peripheral indirect addressing mode

DMA0CONbits.MODE = 0b10; // Configure DMA for Continuous, Ping-Pong mode

DMA0PAD = (volatile unsigned int)&ADC1BUF0; // Point DMA to ADC1BUF0

DMA0CNT = DMA_TOTAL_LEN-1; // DMA transfer count

DMA0REQ =13; // Select ADC1 as DMA Request source

DMA0STA = __builtin_dmaoffset(&adcDmaA);

DMA0STB = __builtin_dmaoffset(&adcDmaB);

IFS0bits.DMA0IF = 0; //Clear the DMA interrupt flag bit

IEC0bits.DMA0IE = 1; //Set the DMA interrupt enable bit

DMA0CONbits.CHEN=1; //Enable DMA

AD1CON1bits.ADON = 1; //Enable ADC

while(! adc_new_data());//wait for first set of data

}

unsigned int (*adcDmaPtr)[DMA_SEG_COUNT][DMA_SEG_LEN];

#define adcDma (*adcDmaPtr) //convinient macro to access last updated buffer

volatile unsigned int adcDmaAge = 0; //number of times interrupt was call since last succesful adc_new_data

void __attribute__((__interrupt__,no_auto_psv)) _DMA0Interrupt(void)

{

//_LAT(pinLed) = DMACS1bits.PPST0; //for debug

if(adcDmaAge<0xFFFF) adcDmaAge++;

if(DMACS1bits.PPST0) //adcDMAptr stores last access buffer by Ping-Pong DMA mode

adcDmaPtr = &adcDmaA;

else

adcDmaPtr = &adcDmaB;

IFS0bits.DMA0IF = 0; //Clear the DMA0 Interrupt Flag

}

double adcAvg[DMA_SEG_LEN];

#define ADC_AVG_LONG_LEN 16

double adcAvgLong[DMA_SEG_LEN]; //average over ADC_AVG_LONG_LEN calls to adc_new_data

unsigned int adcMin[DMA_SEG_LEN];

unsigned int adcMax[DMA_SEG_LEN];

char adc_new_data_first = 1;

unsigned long adc_new_data(){

unsigned long interval_us = 0;

if(adcDmaAge >= 1){

interval_us = (unsigned long)adcDmaAge * DMA_INTERVAL_US; //how much time passed since last succesful call to this function

adcDmaAge = 0; //reset, will be incremented by DMA interupt

//compute average ADC values

unsigned char i,j;

for(i=0;i<DMA_SEG_COUNT;i++){

adcAvg[i] = 0;

for(j=0;j<DMA_SEG_LEN;j++){

if(0==j){

adcMin[i]= adcDma[i][j];

adcMax[i]= adcDma[i][j];

}else{

if(adcDma[i][j]<adcMin[i]) adcMin[i]= adcDma[i][j];

if(adcDma[i][j]>adcMax[i]) adcMax[i]= adcDma[i][j];

}

adcAvg[i] += adcDma[i][j]; //use pointer to last updated buffer adcDmaA or adcDmaB, that is updated by DMA interrupt

}

adcAvg[i] /= DMA_SEG_LEN;

if(adc_new_data_first)

adcAvgLong[i] = adcAvg[i];

else

adcAvgLong[i] = low_pass_filter(adcAvg[i],adcAvgLong[i],ADC_AVG_LONG_LEN);

};

}

adc_new_data_first = 0;

return interval_us;

}

void adc_debug_dump1(){

unsigned char i,j;

//printf("adcDMAptr=%u adcDmaAge= %u\n", (unsigned int)adcDmaPtr, adcDmaAge);

for(i=0;i<DMA_SEG_COUNT;i++){

printf("an%u A=",i);

for(j=0;j<DMA_SEG_LEN;j++){

printf("%04u ",adcDmaA[i][0]);

}

printf(" adcAvg=%#6.1f (%#6.1f mV) \n",adcAvg[i],adc_to_mv(adcAvg[i]));

printf("an%u B=",i);

for(j=0;j<DMA_SEG_LEN;j++){

printf("%04u ",adcDmaB[i][0]);

}

printf(" adcMin=%u adcMax=%u dif=%u\n",adcMin[i],adcMax[i],adcMax[i]-adcMin[i]);

};

printf("\n\n" );

}

void adc_debug_dump2(){

unsigned char i;

for(i=0;i<DMA_SEG_COUNT;i++){

printf("%.1f,%d,",adcAvgLong[i],adcMax[i]-adcMin[i]);

};

printf("\n");

}