I have been tasked with debugging an application built with MQXLite and trying to get it to enter & exit VLLS2.
I am in the process of determining if the peripherals are being disabled prior to entry into VLLS2 to ensure those are not causing it to hang in an "undefined" state.
I have tried to verify the VLLS2 mode is properly configured (as compared with a bare-metal test application that works). It looks like all the register settings are being correctly made.
Symptoms: The processor appears to be entering VLLS2, but does not respond to the configured wake-up pins (one is a reed-switch). Attempting to pause the debugger (JLink) gets a "halt failed" message. When attempting to resume or reset the processor, it gives the appearance of having lost the application - the debug stack trace indicates trying to run from address 0xFFFFFFFF like it has tried to go to an undefined or lost memory address.
Question #1: How should the necessary ISRs be defined or installed (and where)?
We are using RTC and two external pins for wake up sources. They appear to be correctly defined for the LLWU module. I know that a LLWU ISR and Port ISR will be required for the LLWU module to call before it goes to the reset path. I do not know if they are getting correctly established. The MQXLite code as inherited is using both the _int_install_kernel_isr() and _int_install_isr() routines/methods with both types of isr table references (inside the RTOS and outside the RTOS).
Question #2: Is there a more specific application note for setting up the power management in MQXLite?
I have already gone through AN4503, AN4447 and AN4470. The LPM driver referenced appears to only be available for full MQX and not part of the MQXLite (as downloaded in PExDriverSuite_v10.4). The afore mentioned bare-metal test application that works is known to be disabling all peripherals prior to VLLS2 entry. The MQXLite based application is unknown.