Debug and old IRQ

RE: Debug and old IRQ

Fabien Comte — Fri, 04 Mar 2016 12:01:20 GMT

chip was broken with __disable_irq(); finally i changed the chip on my board

RE: Debug and old IRQ

Susheel Nuguru — Fri, 04 Mar 2016 10:25:36 GMT

I still do not understand why the chip is bricked? debugger accessing chip from SWD is a different thing. I think there is a reset happening at the early phase of your startup, so your chip is in infinite loop of reset.

RE: Debug and old IRQ

Fabien Comte — Thu, 03 Mar 2016 21:03:22 GMT

I did that because when a peripheral is working and debugger restart application you get some unexpected irq (end of started DMA xfer) and application crash. With that lines, no more issue, debug by nRF52 DK is stable in my case.

RE: Debug and old IRQ

Susheel Nuguru — Thu, 03 Mar 2016 19:35:58 GMT

Why did you do that???? We were talking about disabling peripheral interrupts and not using __disable_irq because it was disabling SVC exception also. Clearing all bits in ICER register means everything except reset, NMI and hardfault are disabled. This is out of my knowledge of to what debugger needs to halt the CPU here. I will talk to few other guys here tomorrow and see if there is any possibility to unbrick your device.

RE: Debug and old IRQ

Fabien Comte — Thu, 03 Mar 2016 12:16:25 GMT

For the brocken CPU is there a hard way to erase all ?

RE: Debug and old IRQ

Fabien Comte — Thu, 03 Mar 2016 12:15:19 GMT

I propose

// disable all external interrupts
		NVIC->ICER[0] = 0xFFFFFFFF;
		NVIC->ICER[1] = 0xFFFFFFFF;
		NVIC->ICER[2] = 0xFFFFFFFF;
		NVIC->ICER[3] = 0xFFFFFFFF;
		NVIC->ICER[4] = 0xFFFFFFFF;
		NVIC->ICER[5] = 0xFFFFFFFF;
		NVIC->ICER[6] = 0xFFFFFFFF;
		NVIC->ICER[7] = 0xFFFFFFFF;
		
		// clear all external pending interrupts
		NVIC->ICPR[0] = 0xFFFFFFFF;
		NVIC->ICPR[1] = 0xFFFFFFFF;
		NVIC->ICPR[2] = 0xFFFFFFFF;
		NVIC->ICPR[3] = 0xFFFFFFFF;
		NVIC->ICPR[4] = 0xFFFFFFFF;
		NVIC->ICPR[5] = 0xFFFFFFFF;
		NVIC->ICPR[6] = 0xFFFFFFFF;
		NVIC->ICPR[7] = 0xFFFFFFFF;

RE: Debug and old IRQ

Fabien Comte — Thu, 03 Mar 2016 12:15:00 GMT

I did it and i have a CPU that i cannot recover with SWD...

RE: Debug and old IRQ

Susheel Nuguru — Thu, 03 Mar 2016 12:07:01 GMT

True, SVC interrupt needs to be enabled before calling sd_softdevice_enable. __disable_irq seems more dangerous than i thought :). Just disable all peripheral interrupts instead

RE: Debug and old IRQ

Fabien Comte — Thu, 03 Mar 2016 11:32:59 GMT

See that if you get some issues devzone.nordicsemi.com/.../

RE: Debug and old IRQ

Fabien Comte — Thu, 03 Mar 2016 10:56:23 GMT

Thank you.

RE: Debug and old IRQ

Susheel Nuguru — Wed, 02 Mar 2016 17:07:18 GMT

Hi,

   __disable_irq();

I think this is ARM CMSIS funtion and it will disable all IRQ. This should be ok as you are doing it before enabling softdevice.