Software ACK failed in NRF24LE1.

[junma]

Hi all,

I tried to implement a software ACK between two NRF24LE1 devices, but failed. In my tick_interrupt_ISR, I send a frame from device_A to device_B, and I want to wait for the ACK from device_B still in the tick_interrupt_ISR. To the detail, there is a flag variable in RF_IRQ(RF ISR), if a new RF frame is received, it will be set. And then the code in tick_interrupt_ISR will read the flag variable and check the received RF data, to determine whether it is a wanted ACK frame.

The simplified RF_IRQ ISR code is shown below:

void RF_IRQ(void) interrupt INTERRUPT_RFIRQ
{
  uint8_t irq_flags;

  irq_flags = hal_nrf_get_clear_irq_flags();// Read and clear IRQ flags from radio
	
  switch(irq_flags)
  {
	// If data received
	case (1 << (uint8_t)HAL_NRF_RX_DR):
	    // Read payload
        while(!hal_nrf_rx_fifo_empty())
	     {
			hal_nrf_read_rx_payload(RX_buffer);
	     }
	    // Flush RX FIFO
	    hal_nrf_flush_rx();
	    radio_receive_ready = true;       //The flag is set here!!!
        LED3 = ~LED3;
	    break;
		
	// If Transmission success
    case (1 << (uint8_t)HAL_NRF_TX_DS):
       radio_send_busy = false;
       break;
	
    // Transmission failed (maximum re-transmits)
    case (1 << (uint8_t)HAL_NRF_MAX_RT):
       hal_nrf_flush_tx();
       radio_send_busy = false;
       break;
     default:
       break;
  }
}

The simplified tick ISR is shown below:

void rtc2_isr(void) interrupt INTERRUPT_TICK
{
	RTC2CON &= 0xfe;	//Disable RTC2 function 1111 1110
    TX_buffer[7] = 0x12;	//control data to device_B
	
	RF_Send(TX_buffer, RF_PLOAD_WIDTH);	//Send a control frame to device_B

       //Try to wait the ACK here
//        while(!radio_receive_ready );         // line121   
    if( radio_receive_ready == true)
    {
         LED4 = ~LED4;    //The LED4 never changed status!!!
    }
}

My test results are shown below:

1. If "line121" is commented out, the LED3 always changes each time I send a frame, but LED4 never changes;

2. If "line121" is NOT commented, the device seems to be gotten stuck, and BOTH LED3 & LED4 never changes. The tick interrupt has a lower priority than RF interrupt, and I wonder if the interrupt nesting error happend.

Could you please help me analyze this problem, thanks in advance!

Best Regards, Junma

[Hung Bui]

@Junma: Could you let me know how you set the priority level with IP1 and IP0 register ? Could you update the question with your full configuration of the interrupt? I tested here and it worked fine.