PIT timer of SPC560P50L5 to be used for wake up

[Central SUPPORT]

We use SPC560P50L5 in an automotive-qualified battery management system for starter batteries. PIT timer of this device should be able to generate a wake-up interrupt when in low-power mode.

At this moment, PIT timer 3 is already working to generate an interrupt at the end of a certain time period. The user manual states that it is possible to use the PIT timer to leave low-power mode (STOP0). But it is unclear which registers are used for that, and how we have to configure them. 

NOTE: This question and answer originated from a customer support case which was handled by us. We regularly review support cases and add any helpful ones here for all to benefit from.

[Central SUPPORT · Accepted solution]

For PIT to be used for wake-up it needs some additional settings, so let me summarize following three main points:

1.     CLK has to be enabled for PIT, but since PIT3 is already working I suppose that this point is done

-      Register PITMCR_MDIS

2.    Interrupt has to be enabled and you have to clear the flag after an interrupt has occured.

-      Register TCTRL3 for enable

-      Register TFLG3_TIF for clearing flag

3.    Configure the STOP0 mode to keep the PIT enabled and working

-      ME_STOP0_MC for configuration of used mode, important is that SYSCLK is running.

-      ME_LP_PC0_STOP0 should be enabled.

-      ME_PCTL92_LP_CFG should be set to “000�?, which selects ME_LP_PC0 configuration.