TM4C123GH6PM: ADC ---> Memory using uDMA.

Chris Mcgarvey

Part Number: TM4C123GH6PM
Other Parts Discussed in Thread: EK-TM4C123GXL

I am trying to just simply read the temperature sensor from the ADC0 with uDMA, then read it over UART.

Here is my code: https://paste.ofcode.org/37m72pGspzZ47eUVU5mMmwq

Every time I go into calculate temperature, and the ADC gets triggered, the uDMA goes into a bus error. I have no idea what I am doing. I am trying to understand uDMA and how to use it, but this simple program is killing me. I've already tested to see if it works without UDMA. I also know that I'm only using one register in the AVG, just trying to start small then plan on adding the others when I get one to work.

I have read others people code and problems, and I feel like I have done everything they have suggested. Maybe not. What am I blatantly missing? I appreciate any help. Thank you very much.

over 4 years ago

0 Charles Tsai over 4 years ago

TI__Guru**** 190806 points

Hi,

There is a ready to use example for ADC with uDMA. Please find the example in:

C:\ti\TivaWare_C_Series-2.2.0.295\examples\boards\ek-tm4c123gxl\adc_udma_pingpong

Compare this example with yours and you should be able to narrow down the fault. Please see below link to an app note about diagnosing faults in the system.

0 Chris Mcgarvey over 4 years ago in reply to Charles Tsai

Prodigy 20 points

Hello, so like I already stated. I've followed all those examples, and I tried the debugging. The NVIC_fault_stat is 0. Like I said already, the bus fault happens in the uDMA not the NVIC.

Here is my code again because I'm guessing you aren't allowed to click links.

#include <stdint.h>
#include <stdbool.h>
#include "inc/hw_types.h"
#include "inc/hw_memmap.h"
#include "inc/tm4c123gh6pm.h"
#include "driverlib/sysctl.h"
#include "driverlib/gpio.h"
#include "driverlib/pin_map.h"
#include "driverlib/timer.h"
#include "driverlib/uart.h"
#include "driverlib/adc.h"
#include "utils/uartstdio.h"
#include "driverlib/interrupt.h"
#include "driverlib/udma.h"
//********************

typedef struct{
    uint16_t adcBuffer[8];
    uint16_t AVG;
    uint16_t C;
    uint16_t F;
}Temp_t;


typedef struct{

    unsigned char input;

}UART_t;


void calculate_avg_temperature(Temp_t *temp_t);
//*******************


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

uint8_t DMAControlTable[1024];

//*******************
int main(void)
{

      //Config System Clock
     SysCtlClockSet(SYSCTL_SYSDIV_5 | SYSCTL_XTAL_16MHZ | SYSCTL_USE_PLL | SYSCTL_OSC_MAIN );

     Temp_t temp_t = {0};

     volatile UART_t uart_t;


     //Config UART
     SysCtlPeripheralEnable(SYSCTL_PERIPH_UART0);
     SysCtlPeripheralEnable(SYSCTL_PERIPH_GPIOA);

     GPIOPinConfigure(GPIO_PA1_U0TX);
     GPIOPinConfigure(GPIO_PA0_U0RX);
     GPIOPinTypeUART(GPIO_PORTA_BASE, GPIO_PIN_1 | GPIO_PIN_0);
     UARTConfigSetExpClk(UART0_BASE, SysCtlClockGet(), 9600UL, UART_CONFIG_WLEN_8 | UART_CONFIG_STOP_ONE | UART_CONFIG_PAR_NONE);
     UARTStdioConfig(0, 9600, SysCtlClockGet());
     //

      SysCtlPeripheralEnable(SYSCTL_PERIPH_ADC0);

     //Config uDMA
       SysCtlPeripheralEnable(SYSCTL_PERIPH_UDMA);

       uDMAEnable();
       uDMAControlBaseSet(DMAControlTable);

       uDMAChannelAttributeDisable(UDMA_CH14_ADC0_0, UDMA_ATTR_ALL);
       uDMAChannelAttributeDisable(UDMA_CH14_ADC0_0 | UDMA_ALT_SELECT, UDMA_ATTR_ALL);

       uDMAChannelAttributeEnable(UDMA_CH14_ADC0_0, UDMA_ATTR_USEBURST);

       uDMAChannelControlSet(UDMA_CH14_ADC0_0 | UDMA_PRI_SELECT, UDMA_SIZE_16 | UDMA_SRC_INC_NONE | UDMA_DST_INC_16 | UDMA_ARB_1);

       uDMAChannelTransferSet(UDMA_CH14_ADC0_0 | UDMA_PRI_SELECT, UDMA_MODE_BASIC, (void*)(ADC0_SSFIFO0_R), temp_t.adcBuffer, sizeof(temp_t.adcBuffer));

       uDMAChannelEnable(UDMA_CH14_ADC0_0);



     //Config ADC


     ADCClockConfigSet(ADC0_BASE, ADC_CLOCK_SRC_PIOSC | ADC_CLOCK_RATE_HALF, 1);

     SysCtlDelay(10);

     ADCSequenceDisable(ADC0_BASE, 0u);

     ADCSequenceConfigure(ADC0_BASE, 0, ADC_TRIGGER_PROCESSOR, 0);
     ADCSequenceStepConfigure(ADC0_BASE, 0, 0, ADC_CTL_TS | ADC_CTL_END | ADC_CTL_IE);
     ADCSequenceEnable(ADC0_BASE, 0);
     ADCSequenceDMAEnable(ADC0_BASE, 0);




    while(1)
    {
    calculate_avg_temperature(&temp_t);
        UARTprintf("C %3d\t", temp_t.C);
    }
}


//Calculate the average
void calculate_avg_temperature(Temp_t *temp_t){

    while(!(uDMAChannelModeGet(UDMA_CH14_ADC0_0 | UDMA_PRI_SELECT) == UDMA_MODE_STOP)){
        ADCProcessorTrigger(ADC0_BASE, 0);
        while(!(ADCIntStatus(ADC0_BASE, 0, false))){};
        ADCIntClear(ADC0_BASE, 0);
    };


    temp_t->AVG = (temp_t->adcBuffer[0]);
    temp_t->C = (1475 - (2475 * temp_t->AVG) / 4096)/10;
    temp_t->F = ((temp_t->C * 9) + 160) / 5;

    uDMAChannelTransferSet(UDMA_CH14_ADC0_0 | UDMA_PRI_SELECT, UDMA_MODE_BASIC, (void*)(ADC0_SSFIFO0_R), temp_t->adcBuffer, sizeof(temp_t->adcBuffer));
    uDMAChannelEnable(UDMA_CH14_ADC0_0);

}

So like I said already, when the ADCProcessorTrigger happens, the uDMA bus fault triggers. The datasheet doesn't give any more information on this and what causes it.

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TM4C123GH6PM: ADC ---> Memory using uDMA.