TM4C1231H6PM: Errata SYSCTL#04

Jacky Wang43

Prodigy 245 points

Part Number: TM4C1231H6PM

Hi,

My system is running with FreeRTOS, it has interrupts and the system clock is 50MHz.

For this errata's requirement,

what does it mean by "Interrupt must be disabled" ?

Also, I would like to try to reproduce this errata on my system. Is there a way to quickly reproduce this? For example if there is a way to increase the likelihood of the system from not waking up from sleep mode due to this errata.

Any help is greatly appreciated. Thanks in advance.

Jacky

over 5 years ago

0 Bob Crosby over 5 years ago

TI__Guru 72500 points

The condition is not easy to reproduce as it only happens intermittently on some devices. It happens when relying on an NMI or a debug request to wake the processor.

0 Jacky Wang43 over 5 years ago in reply to Bob Crosby

Prodigy 245 points

Thanks for the quick reply. Do you know what the second bullet point in the description mean? Does it mean the interrupt mechanism is not used at all throughout the system or does it mean the interrupt is disabled before entering sleep mode?

0 Bob Crosby over 5 years ago in reply to Jacky Wang43

TI__Guru 72500 points

Interrupts disabled before entering sleep mode.

0 Jacky Wang43 over 5 years ago in reply to Bob Crosby

Prodigy 245 points

Just another question that popped out as I was pondering,

Here is the TI driverlib implementation of entering sleep mode:

void
SysCtlSleep(void)
{
    //
    // Wait for an interrupt.
    //
    CPUwfi();
}

If I were to disable interrupt before entering sleep mode, wouldn't it be natural that the processor never wakes up as the implementation is doing a wait for interrupt (WFI)? I am a little confused with this errata...

Thanks,

Jacky

0 Bob Crosby over 5 years ago in reply to Jacky Wang43

TI__Guru 72500 points

With the exceptions of a non-maskable interrupt (NMI) or a debug request. I agree, the wording of the advisory is somewhat confusing.

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TM4C1231H6PM: Errata SYSCTL#04