MSPM0G3507: ADC noise issue, It seems to be related to Sample Clock Divider and CPUCLK

Hi,

Could you provide your test code with this issue you observed? We can take a look into it and check what could be wrong about it. 

Best regards,

Cash Hao

Hi Cash Hao,

Thanks, I import "adc12_triggered_by_timer_event_LP_MSPM0G3507_nortos_ticlang" from mspm0_SDK.

Below are the changes I made
1. Add UART for print (UART0, Baud Rate : 115200)

2.Clock tree : Enable HFXT(40M), select XTAL, Select HFCLK, set QDIV to x4,  select SYSPLL0, set  UDIV to /2

3. in ADC12, change ADC clock source to ULPCLK, set Sample Clock Divider to Divide by 24, set Reference Voltage to VREF

4. Enable VREF, mode set to External, VREF+- enabled and External voltage set to 1.5

FB

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#include "ti_msp_dl_config.h"

#define ADC_SAMPLE_SIZE (1024)
/* When FIFO is enabled 2 samples are compacted in a single word */
#define ADC_FIFO_SAMPLES (ADC_SAMPLE_SIZE >> 1)

uint16_t gADCSamples[ADC_SAMPLE_SIZE];
volatile bool gCheckADC;

void SendString(char *String, int Length)
{
    int i;
    for(i = 0 ;i < Length ; i++)
    {
        DL_UART_Main_transmitData(UART_0_INST, String[i]);
        delay_cycles(8000);
    }

}

int main(void)
{
    char Data[100];
    int i;
    SYSCFG_DL_init();

    /* Configure DMA source, destination and size */
    DL_DMA_setSrcAddr(DMA, DMA_CH0_CHAN_ID,
        (uint32_t) DL_ADC12_getFIFOAddress(ADC12_0_INST));

    DL_DMA_setDestAddr(DMA, DMA_CH0_CHAN_ID, (uint32_t) &gADCSamples[0]);
    DL_DMA_setTransferSize(DMA, DMA_CH0_CHAN_ID, ADC_FIFO_SAMPLES);

    DL_DMA_enableChannel(DMA, DMA_CH0_CHAN_ID);

    /* Setup interrupts on device */
    NVIC_EnableIRQ(ADC12_0_INST_INT_IRQN);

    gCheckADC = false;

    DL_ADC12_startConversion(ADC12_0_INST);

// for test ADC noise
    while (false == gCheckADC) {
        __WFE();
    }

    DL_ADC12_stopConversion(ADC12_0_INST);
    DL_DMA_disableChannel(DMA, DMA_CH0_CHAN_ID);

    for(i=0;i<ADC_SAMPLE_SIZE;i++)
    {
        sprintf(Data,"%04d\n",gADCSamples[i]);
        SendString(Data,5);
    }

// end
    __BKPT(0);

    while (1) {
        __WFI();
    }
}

void ADC12_0_INST_IRQHandler(void)
{
    switch (DL_ADC12_getPendingInterrupt(ADC12_0_INST)) {
        case DL_ADC12_IIDX_DMA_DONE:
            gCheckADC = true;
            break;
        default:
            break;
    }
}

/**
 * These arguments were used when this file was generated. They will be automatically applied on subsequent loads
 * via the GUI or CLI. Run CLI with '--help' for additional information on how to override these arguments.
 * @cliArgs --device "MSPM0G350X" --package "LQFP-64(PM)" --part "Default" --product "mspm0_sdk@2.00.01.00"
 * @versions {"tool":"1.20.0+3587"}
 */

/**
 * Import the modules used in this configuration.
 */
const ADC12  = scripting.addModule("/ti/driverlib/ADC12", {}, false);
const ADC121 = ADC12.addInstance();
const Board  = scripting.addModule("/ti/driverlib/Board");
const SYSCTL = scripting.addModule("/ti/driverlib/SYSCTL");
const UART   = scripting.addModule("/ti/driverlib/UART", {}, false);
const UART1  = UART.addInstance();
const VREF   = scripting.addModule("/ti/driverlib/VREF");

/**
 * Write custom configuration values to the imported modules.
 */
const divider9       = system.clockTree["UDIV"];
divider9.divideValue = 2;

const multiplier2         = system.clockTree["PLL_QDIV"];
multiplier2.multiplyValue = 4;

const mux4       = system.clockTree["EXHFMUX"];
mux4.inputSelect = "EXHFMUX_XTAL";

const mux8       = system.clockTree["HSCLKMUX"];
mux8.inputSelect = "HSCLKMUX_SYSPLL0";

const mux12       = system.clockTree["SYSPLLMUX"];
mux12.inputSelect = "zSYSPLLMUX_HFCLK";

const pinFunction4       = system.clockTree["HFXT"];
pinFunction4.enable      = true;
pinFunction4.inputFreq   = 40;
pinFunction4.HFXTStartup = 100;

ADC121.$name                          = "ADC12_0";
ADC121.repeatMode                     = true;
ADC121.adcMem0chansel                 = "DL_ADC12_INPUT_CHAN_4";
ADC121.sampleTime0                    = "62.5 ns";
ADC121.powerDownMode                  = "DL_ADC12_POWER_DOWN_MODE_MANUAL";
ADC121.enableFIFO                     = true;
ADC121.configureDMA                   = true;
ADC121.sampCnt                        = 6;
ADC121.enabledDMATriggers             = ["DL_ADC12_DMA_MEM10_RESULT_LOADED"];
ADC121.enabledInterrupts              = ["DL_ADC12_INTERRUPT_DMA_DONE"];
ADC121.adcMem0vref                    = "VREF";
ADC121.sampClkSrc                     = "DL_ADC12_CLOCK_ULPCLK";
ADC121.sampClkDiv                     = "DL_ADC12_CLOCK_DIVIDE_24";
ADC121.peripheral.$assign             = "ADC0";
ADC121.peripheral.adcPin4.$assign     = "PB25";
ADC121.adcPin4Config.$name            = "ti_driverlib_gpio_GPIOPinGeneric0";
ADC121.DMA_CHANNEL.$name              = "DMA_CH0";
ADC121.DMA_CHANNEL.addressMode        = "f2b";
ADC121.DMA_CHANNEL.peripheral.$assign = "DMA_CH0";


SYSCTL.forceDefaultClkConfig = true;
SYSCTL.clockTreeEn           = true;

UART1.$name                            = "UART_0";
UART1.targetBaudRate                   = 115200;
UART1.peripheral.rxPin.$assign         = "PA11";
UART1.peripheral.txPin.$assign         = "PA10";
UART1.txPinConfig.$name                = "ti_driverlib_gpio_GPIOPinGeneric3";
UART1.txPinConfig.direction            = scripting.forceWrite("OUTPUT");
UART1.txPinConfig.hideOutputInversion  = scripting.forceWrite(false);
UART1.txPinConfig.onlyInternalResistor = scripting.forceWrite(false);
UART1.txPinConfig.passedPeripheralType = scripting.forceWrite("Digital");
UART1.rxPinConfig.$name                = "ti_driverlib_gpio_GPIOPinGeneric4";
UART1.rxPinConfig.hideOutputInversion  = scripting.forceWrite(false);
UART1.rxPinConfig.onlyInternalResistor = scripting.forceWrite(false);
UART1.rxPinConfig.passedPeripheralType = scripting.forceWrite("Digital");

VREF.basicVrefPins          = "VREF+-";
VREF.basicMode              = "DL_VREF_ENABLE_DISABLE";
VREF.basicExtVolt           = 1.5;
VREF.vrefPosPinConfig.$name = "ti_driverlib_gpio_GPIOPinGeneric1";
VREF.vrefNegPinConfig.$name = "ti_driverlib_gpio_GPIOPinGeneric2";

/**
 * Pinmux solution for unlocked pins/peripherals. This ensures that minor changes to the automatic solver in a future
 * version of the tool will not impact the pinmux you originally saw.  These lines can be completely deleted in order to
 * re-solve from scratch.
 */
pinFunction4.peripheral.$suggestSolution           = "SYSCTL";
pinFunction4.peripheral.hfxInPin.$suggestSolution  = "PA5";
pinFunction4.peripheral.hfxOutPin.$suggestSolution = "PA6";
Board.peripheral.$suggestSolution                  = "DEBUGSS";
Board.peripheral.swclkPin.$suggestSolution         = "PA20";
Board.peripheral.swdioPin.$suggestSolution         = "PA19";
UART1.peripheral.$suggestSolution                  = "UART0";
VREF.peripheral.$suggestSolution                   = "VREF";
VREF.peripheral.vrefPosPin.$suggestSolution        = "PA23";
VREF.peripheral.vrefNegPin.$suggestSolution        = "PA21";

Hi,

Which SDK version you are using? 

It would be much preferred if you can go to your CCS workspace and compress your project file and send it here. 

Best regards,

Cash Hao

Err80M.zip

Hi Cash,

FYI, and this file is modify from "mspm0_sdk_2_00_01_00" "adc12_max_freq_dma_LP_MSPM0G3507_nortos_ticlang"

In addition, I did some verification today. Since the error is fixed to occur every 12 transactions and the wrong value, I tried to set "Enable DMA Triggers" from MEM10 to MEM11. This error will not exist. Is there a reasonable explanation?

Sounds suspiciously like this:

https://e2e.ti.com/support/microcontrollers/arm-based-microcontrollers-group/arm-based-microcontrollers/f/arm-based-microcontrollers-forum/1393962/mspm0g3507-adc-dma-samples-count

Where the DMA grabs a sample before it is ready.

Hi,

It should not related to that e2e issue. 

In your DMA configuration, the source length is Word(4 bytes). One ADC result is 2 bytes. So, the DMA move 2 ADC results in one time. And DMA Samples Count is 6. So, DMA will move 6*2 = 12 ADC results in a row. 

Since your DMA trigger is MEM10, it only contains 11 ADC results. Due to DMA will move 12 ADC results in a row. And the ADC result saved in the MEMRESx register is in FIFO mode. The DMA will move (11 new ADC result and 1 previous ADC result). That is why you seen this issue. 

Best regards,

Cash Hao