MCU Stops Responding

Question

Hi Everyone,

I am working on a project which involves reading data from an accelerometer ( MC3672 ) using NRF52832.

Currently sampling is done via the data ready pin, which is sensed by GPIOTE module and a flag is set which then

gets processed in the main loop.

The program would work fine for a few minutes before the MCU would stop responding all of a sudden and this is seen

by an increase in current consumption from 2mA to 9mA. Initially, I thought that it was due to it being stuck in a endless loop,

however after some debugging, I have nailed it down to the line that it would stop at, but I have no idea what is causing this.

Code for reading data from the accelerometer in the main loop

MCU would stop at the M_DRV_MC36XX_HandleINT(&accel_int) line

ie I would see Handle Int printed but not Handle Int Done in the RTT viewer.

					if(interrupt_flag)
					{						
						uint8_t n;
						spi_change(SPIM0_SS_ACCEL_PIN);			
						s_m_drv_mc36xx_int_t accel_int;
						NRF_LOG_INFO("Handle Int\r\n");
						NRF_LOG_FLUSH();
						M_DRV_MC36XX_HandleINT(&accel_int);
						NRF_LOG_INFO("Handle Int Done\r\n");
						NRF_LOG_FLUSH();
						n = M_DRV_MC36XX_ReadDataBurst(accel,ACCEL_FIFO_THRESHOLD);
						spi_change(SPIM0_SS_NAND_PIN);
						interrupt_flag = false;											
					}

M_DRV_MC36XX_HandleINT(&accel_int) function

Execution stops at _M_DRV_MC36XX_REG_WRITE(E_M_DRV_MC36XX_REG_STATUS_2, &_bRegStatus2, 1);

Eg I see Accel H printed but not Accel E

int M_DRV_MC36XX_HandleINT(s_m_drv_mc36xx_int_t *ptINT_Event)
{
    uint_dev _bRegStatus2 = 0;
    _M_DRV_MC36XX_REG_READ(E_M_DRV_MC36XX_REG_STATUS_2, &_bRegStatus2, 1);

    ptINT_Event->bWAKE =                                                    \
        _M_DRV_MC36XX_REG_STATUS_2_INT_WAKE(_bRegStatus2);
    ptINT_Event->bACQ =                                                     \
        _M_DRV_MC36XX_REG_STATUS_2_INT_ACQ(_bRegStatus2);
    ptINT_Event->bFIFO_EMPTY =                                              \
        _M_DRV_MC36XX_REG_STATUS_2_INT_FIFO_EMPTY(_bRegStatus2);
    ptINT_Event->bFIFO_FULL =                                               \
        _M_DRV_MC36XX_REG_STATUS_2_INT_FIFO_FULL(_bRegStatus2);
    ptINT_Event->bFIFO_THRESHOLD =                                          \
        _M_DRV_MC36XX_REG_STATUS_2_INT_FIFO_THRESH(_bRegStatus2);
    ptINT_Event->bSWAKE_SNIFF =                                             \
        _M_DRV_MC36XX_REG_STATUS_2_INT_SWAKE_SNIFF(_bRegStatus2);

		NRF_LOG_INFO("Accel H\r\n");
		NRF_LOG_FLUSH();
/** clear interrupt flag */
#ifdef    M_DRV_MC36XX_CFG_BUS_SPI
    _M_DRV_MC36XX_REG_WRITE(E_M_DRV_MC36XX_REG_STATUS_2, &_bRegStatus2, 1);
#endif
		NRF_LOG_INFO("Accel E\r\n");
		NRF_LOG_FLUSH();
    return (M_DRV_MC36XX_RETCODE_SUCCESS);
}

The function calls the SPI function to transfer the data

#define _M_DRV_MC36XX_REG_WRITE(bRegAddr, pbDataBuf, bLength) \
mcube_write_regs(0, 0, bRegAddr, pbDataBuf, bLength)

This is the bit I dont understand, all code execute fine and I can see Accel done printed before

the MCU crashes.

int8_t mcube_write_regs(bool bSpi, uint8_t chip_select, uint8_t reg,       \
                         uint8_t *value, uint8_t size)
{
    /** Please implement I2C/SPI write function from platform SDK */
    /** 0 = SPI, 1 = I2C */
	  uint8_t CMD[1+size];
		CMD[0] = reg;
		memcpy(&CMD[1], value, size);
    if(!bSpi) {
			CMD[0] &= ~(1UL << 7);
			CMD[0] |= 1UL << 6;
        /** SPI write function */
			Serialize_SPI(CMD,1+size,NULL,0,true);
			NRF_LOG_INFO("Accel done\r\n");
			NRF_LOG_FLUSH();
//			Serialize_SPI_Write(CMD,1+size,true);
    } else {
        /** I2C write function */
    } 

    return 0;
}

I am trying to find a way to analyze this with a Saleae logic analyser as they dont support repeat trigger

and this problem only occurs once and at a random time.

Thanks for the help.

Rgs,

Bryan Hsieh