How to know that the S912ZVCA19F0MLF microcontroller has entered the STOP mode successfully?

[harshajk]

Hi,

I am using a S912ZVCA19F0MLF microcontroller based on S12Z architecture.
I am trying to put the microcontroller in Deep sleep (STOP mode), I find from the datasheet that the typical current consumption should be around 50uA. But I see there is a current consumption of 7.5mA. Please provide me some suggestions on how to debug that the micro is in STOP mode.

When I execute the instruction "__asm STOP;" the debugger loses the connection. So I cannot know what is happening on the MCU.

Executed functionality:

__asm ANDCC #0x7F;
__asm STOP;‍‍

Questions:

1. How to know that the S912ZVCA19F0MLF has entered STOP mode successfully?

2. Also, do I have to disable all the peripherals before going to sleep? (To reduce the current consumption)

Please let me know how to debug this issue further?

Thanks & Regards,
Harsha

[danielmartynek · Accepted solution]

Hi,

Depending on the setting of the PSTP and the OSCE bit, Stop Mode can be differentiated between Full-Stop Mode (PSTP = 0 or OSCE=0) and Pseudo-Stop Mode (PSTP = 1 and OSCE=1).

So, to enter Full-Stop Mode, the external clock must be disabled.

Since the Bus clock is stopped in Full-Stop mode, you can monitor bus clock as ECLK on PT7 provided ECLKCTL[NECLK] = 0.

The current is probably increased by ADC if you use it.

Please refer to Mask Set Errata S12ZVC_ON23N.

E8188, ADC: High current in Stop Mode.  

The ADC can take a higher current in Stop Mode if the ADC is enabled and conversions have been done.

There is also a workaround. ADC soft-reset must be executed before the MCU enters Stop Mode.

Regards,

Daniel