Exit K20D50 from LLS mode to active mode using UART RX pin to enable LLWU

[joginderrana]

HI,

I am facing a problem in exiting k20d50 controller from the LLS mode to active mode. I did it using external LLWU GPIO pin. But for a certain application I need to enable LLWU mode by pulling the UART RX line active high.

This feature is given in the K20 Sub-Family Reference Manual (page number 67). I am just wondering to know how to activate this mode in MK20DX128VLH5 MCU.  I am using cw-10.5 and is equipped with processor expert.

[perlam_i_au]

I noticed this is a replication from Exit K20D50  from LLS mode active mode using UART RX pin to enable LLWU this other thread I will assume ignore the one I mentioned, and assume this is the  "good one"ok?

[joginderrana]

Exactly, it is.

[perlam_i_au]

You mention you have successfully used LLWU module to get out from LLS mode by external pin trigger but now you would like to do the same but using a UART_RX signal instead external signal trigger, as it's mentioned on AWIC module but I am afraid this is not possible because the LLWU module has been designed specifically to wake up from LLS mode and AWIC module has been designed to get out from STOP and VLPS modes.

Please verify this information on diagrams which describe the interactions for LLWU (Figure 16-1. LLWU block diagram) and AWIC (Figure 9-1. Cortex-M4 Debug Topology) in the reference manual K20P64M50SF0RM. You will notice that wake up sources from AWIC (Table 3-7. AWIC Stop and VLPS Wake-up Sources) are completely different from wake up sources of LLWU (Table 3-13. Wakeup sources for LLWU inputs).

Please let me know if this information is useful or if I have understood your issue.

Have a nice day :P,
Perla

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