ECE3849/sampling.c

#include <stdint.h>
#include <stdbool.h>
#include "inc/tm4c1294ncpdt.h"
#include "driverlib/adc.h"
#include "driverlib/pin_map.h"
#include "driverlib/gpio.h"
#include "driverlib/sysctl.h"
#include "driverlib/interrupt.h"
#include "driverlib/timer.h"
#include "driverlib/udma.h"
#include "sysctl_pll.h"
#include "inc/hw_types.h"
#include "inc/hw_memmap.h"
#include <math.h>
#include "buttons.h"
#include "sampling.h"
#include <xdc/std.h>
#include <xdc/runtime/System.h>
#include <xdc/cfg/global.h>
#include <ti/sysbios/gates/GateHwi.h>


#define DMA

#ifdef DMA
#pragma DATA_ALIGN(gDMAControlTable, 1024)
tDMAControlTable gDMAControlTable[64]; // uDMA control table
#endif

extern uint32_t gSystemClock;   // [Hz] system clock frequency

// is DMA occurring in the primary channel?
volatile bool gDMAPrimary = true;
void ADC_ISR(void) // DMA
{
    ADCIntClearEx(ADC1_BASE, ADC_INT_DMA_SS0); // clear the ADC1 sequence 0 DMA interrupt flag
    // Check the primary DMA channel for end of transfer, and
    // restart if needed.
    if (uDMAChannelModeGet(UDMA_SEC_CHANNEL_ADC10 | UDMA_PRI_SELECT) ==
        UDMA_MODE_STOP) {
        // restart the primary channel (same as setup)
        uDMAChannelTransferSet(UDMA_SEC_CHANNEL_ADC10 | UDMA_PRI_SELECT,
            UDMA_MODE_PINGPONG, (void*)&ADC1_SSFIFO0_R,
            (void*)&gADCBuffer[0], ADC_BUFFER_SIZE/2);
        // DMA is currently occurring in the alternate buffer
        gDMAPrimary = false;
    }
    // Check the alternate DMA channel for end of transfer, and
    // restart if needed.
    // Also set the gDMAPrimary global.
    if (uDMAChannelModeGet(UDMA_SEC_CHANNEL_ADC10 | UDMA_ALT_SELECT) ==
        UDMA_MODE_STOP) {
        // restart the primary channel (same as setup)
        uDMAChannelTransferSet(UDMA_SEC_CHANNEL_ADC10 | UDMA_ALT_SELECT,
             UDMA_MODE_PINGPONG, (void*)&ADC1_SSFIFO0_R,
            (void*)&gADCBuffer[ADC_BUFFER_SIZE/2],
            ADC_BUFFER_SIZE/2);
        // DMA is currently occurring in the primary buffer
        gDMAPrimary = true;
    }
    // The DMA channel may be disabled if the CPU is paused by the debugger
    if (!uDMAChannelIsEnabled(UDMA_SEC_CHANNEL_ADC10)) {
        // re-enable the DMA channel
        uDMAChannelEnable(UDMA_SEC_CHANNEL_ADC10);
    }
}

int32_t getADCBufferIndex(void)
{
    int32_t index;
    uint32_t key = GateHwi_enter(gateHwi0);
    if (gDMAPrimary) { // DMA is currently in the primary channel
        index = ADC_BUFFER_SIZE/2 - 1 -
        uDMAChannelSizeGet(UDMA_SEC_CHANNEL_ADC10 |
        UDMA_PRI_SELECT);
    } else { // DMA is currently in the alternate channel
        index = ADC_BUFFER_SIZE - 1 -
        uDMAChannelSizeGet(UDMA_SEC_CHANNEL_ADC10 |
        UDMA_ALT_SELECT);
    }
    GateHwi_leave(gateHwi0, key);

    return index;
}

void start_sampler() {
    gADCBufferIndex = ADC_BUFFER_SIZE - 1;
    gADCErrors = 0;

    // init DMA
    SysCtlPeripheralEnable(SYSCTL_PERIPH_UDMA);
    uDMAEnable();
    uDMAControlBaseSet(gDMAControlTable);
    // assign DMA channel 24 to ADC1 sequence 0
    uDMAChannelAssign(UDMA_CH24_ADC1_0);
    uDMAChannelAttributeDisable(UDMA_SEC_CHANNEL_ADC10, UDMA_ATTR_ALL);
    // primary DMA channel = first half of the ADC buffer
    uDMAChannelControlSet(UDMA_SEC_CHANNEL_ADC10 | UDMA_PRI_SELECT,
     UDMA_SIZE_16 | UDMA_SRC_INC_NONE | UDMA_DST_INC_16 |
    UDMA_ARB_4);
    uDMAChannelTransferSet(UDMA_SEC_CHANNEL_ADC10 | UDMA_PRI_SELECT,
     UDMA_MODE_PINGPONG, (void*)&ADC1_SSFIFO0_R,
    (void*)&gADCBuffer[0], ADC_BUFFER_SIZE/2);
    // alternate DMA channel = second half of the ADC buffer
    uDMAChannelControlSet(UDMA_SEC_CHANNEL_ADC10 | UDMA_ALT_SELECT,
     UDMA_SIZE_16 | UDMA_SRC_INC_NONE | UDMA_DST_INC_16 |
    UDMA_ARB_4);
    uDMAChannelTransferSet(UDMA_SEC_CHANNEL_ADC10 | UDMA_ALT_SELECT,
     UDMA_MODE_PINGPONG, (void*)&ADC1_SSFIFO0_R,
    (void*)&gADCBuffer[ADC_BUFFER_SIZE/2],
    ADC_BUFFER_SIZE/2);
    uDMAChannelEnable(UDMA_SEC_CHANNEL_ADC10);


    SysCtlPeripheralEnable(SYSCTL_PERIPH_GPIOE);
    GPIOPinTypeADC(GPIO_PORTE_BASE,
                    GPIO_PIN_0); // GPIO setup for analog input AIN3
    // initialize ADC peripherals
    SysCtlPeripheralEnable(SYSCTL_PERIPH_ADC0);
    SysCtlPeripheralEnable(SYSCTL_PERIPH_ADC1);

    // ADC clock
    uint32_t pll_frequency = SysCtlFrequencyGet(CRYSTAL_FREQUENCY);
    uint32_t pll_divisor =
        (pll_frequency - 1) / (16 * ADC_SAMPLING_RATE) + 1; // round up
    ADCClockConfigSet(ADC0_BASE, ADC_CLOCK_SRC_PLL | ADC_CLOCK_RATE_FULL,
                    pll_divisor);
    ADCClockConfigSet(ADC1_BASE, ADC_CLOCK_SRC_PLL | ADC_CLOCK_RATE_FULL,
                    pll_divisor);
    // choose ADC1 sequence 0; disable before configuring
    ADCSequenceDisable(ADC1_BASE, 0);
    ADCSequenceConfigure(ADC1_BASE, 0, ADC_TRIGGER_ALWAYS,
                        0); // specify the "Always" trigger
    // in the 0th step, sample channel 3 (AIN3)
    // enable interrupt, and make it the end of sequence
    ADCSequenceStepConfigure(ADC1_BASE, 0, 0, ADC_CTL_CH3 | ADC_CTL_END | ADC_CTL_IE);
    // enable the sequence. it is now sampling
    ADCSequenceEnable(ADC1_BASE, 0);

    // enable sequence 0 interrupt in the ADC1 peripheral
    //ADCIntEnable(ADC1_BASE, 0); // INT_ADC1SS0

    ADCSequenceDMAEnable(ADC1_BASE, 0); // enable DMA for ADC1 sequence 0
    ADCIntEnableEx(ADC1_BASE, ADC_INT_DMA_SS0); // enable ADC1 sequence 0 DMA interrupt
}