SPI doesn't work when started by Timer

[muhkuhns]

Short: Working Timer. Working SPI. SPI does not work when triggered by timer_handler.

Hello,

I am currently trying to replace delays with timer in my code...

I set up a working timer that goes off every 4 seconds. In the handler that is called I would like to call the function that initiates a measurement and then gets the values afterwards. It does not work in combination. Debugger stops at if (p_spi_instance->disable_all_irq) in the SPI routine. (Flag is not set btw).

If I log via UART instead of any value it only outputs 0.

main.c

//Edit:

static void test_timer_handler(void * p_context)
{
    UNUSED_PARAMETER(p_context);
		printf("Hallo\n");
		hole_temperatur();
}

When I call this function from within the timer handler:

        static int32_t hole_temperatur(void)
    {
    				
    					if (m_transfer_completed) 
    				{	// ADC Temperatur 256 Aufloesung
    					m_transfer_completed = false;	
    					m_tx_data_1B[0] = 0x50; 
    					uint32_t err_code = spi_master_send_recv(SPI_MASTER_0, m_tx_data_1B, 1, m_rx_data_1B, 1);
APP_ERROR_CHECK(err_code);	
    					printf("%d %X %d \n",err_code, m_rx_data_1B[0], m_transfer_completed);
    					nrf_delay_ms(1);
    				}
    				
    					if (m_transfer_completed)
            { //Hole und berechne Temperatur
              m_transfer_completed = false;					
    					m_tx_data_4B[0] = 0x00;
    					m_tx_data_4B[1] = 0xFF;
    					m_tx_data_4B[2] = 0xFF;
    					m_tx_data_4B[3] = 0xFF;
    					uint32_t err_code = spi_master_send_recv(SPI_MASTER_0, m_tx_data_4B, 4, m_rx_data_4B, 4);	
    					APP_ERROR_CHECK(err_code);	
    					printf("%d \n",err_code);
    					nrf_delay_ms(1);
    					printf("%X \n",m_rx_data_4B[1]);
    					//printf("%X \n",m_rx_data_4B[2]);
    					//printf("%X \n",m_rx_data_4B[3]);
    					D2 = m_rx_data_4B[1]<<16 | m_rx_data_4B[2]<<8 | m_rx_data_4B[3];
    					//printf("%d \n",D2);
    					//printf("%s \n", m_transfer_completed ? "true" : "false");
    					dT = (int32_t)D2 - ( (int32_t)Koeff[5] * 256 );				
    					T = 2000 + ((int64_t)dT * Koeff[6]) / 8388608LL;					
    				} return T = (int32_t)T;
    }

It outputs "0 FE 0" So no error. Expected Read Result but transfer not completed! I removed the static from the variable declaration but that didn't help. The flag is meant to be set inside the spi_master_event_handler.

When I remove the if(transfer_completed) from the //Hole und berechne Part I only receive a capital H every 4 seconds. (The "Hallo" is also gone missing)

Well it looks like it is the H from Hallo. With the hallo-printf statement excluded I aint got nothin'.

How else could I realize this? All I could think of is just setting a flag in the timer_handler and check for this in the main()-loop and then execute the code from here. But that wouldn't help me with current consumption, would it? This would also keep the chip awake or would this be better than using delay?

timer_handler {test_flag=true}

    for (;;)
    {
      power_manage();       
            if(test_flag) { printf("%d \n",hole_temperatur()); test_flag=false;}
}

[RK]

What do you mean by 'Debugger stops at .. "? Do you mean you are running the code and the debugger lands on that line even though it doesn't have a breakpoint? Or do you mean you step to that line and single stepping no-longer works, you stay on that line or do you mean something else?

if you step over that line and the debugger never returns, hit the break button to find out where you are. Are you in one of the fault handlers?

Are you trying to debug with the softdevice on and doing something? That won't work, as soon as you hit a breakpoint the softdevice doesn't get its regular interrupts, the timing goes completely out and the softdevice ends up asserting, quite soon, throwing you into one of the fault handlers or the error handler or something else you're not coming back from.

[muhkuhns]

@RK: Thank you for this helpful explanations regarding debugging! I will take good use of them! I let the debugger run to the breakpoint@the call in the handler and then stepped lines (F11). Will look where I land after hitting break. Eh. Where is the "break" button?

@Aryan: Thanks for looking into the code! I was afraid it was to due the execution within an interrupt context.. But I have no clue what my alternatives are. I simply want the measurements to take place every 4 seconds, but of course have the chip consume as less current as possible in between. What is recommended for this case? (Later on it would be even better if it starts the measurement ~3,8seconds after the values got read by the central)