From KL26 to KL16Z128 Sleep Mode Issues

[akselbondoe]

We have been working on developing an industrial sensor node for the last one and half years. In the first prototype phase we have been using the KL26 development board. However, now we have made a PCB with the a KL16Z128 mounted.

It is in the change from KL26 development board to the KL16Z128 that we are experiencing issues now, and specifically with sleep modes. We are using two different kinds of sleep mode:

1. STOP mode for short period of time when connecting to an industrial wireless network. In this mode get woken up successfully by the UART interface with the KL26. However, with the KL16Z128, the UART wakes up the MCU, but all data on the UART turns into nonsense seen from the MCU. We remove the sleep mode (STOP) and the UART data is read normally again.
2. LLS mode when sleeping for longer periods of time in between sensor measurement cycles. In this mode the MCU gets woken up by LLWU, either periodically by the LPTMR0, or occasionally by the UART TX RTS. This functionality works perfectly on the KL26Z, however with the KL16Z the MCU never gets woken by LLWU.

The problems that we experience now impacts the core functionality of our product, and sets the entire project on a hold. If someone knows anything about these issues, and can help, it would be much appreciated.

Best regards,

Aksel Bondø

[Hui_Ma]

Hi,

Could you tell us the KL16 chip's mask set (could be found at chip surface print info second row)?

Customer could find the chip errata info from here.

And it also need to check the MCG clock setting, if KL16 MCG setting is same with KL26?

And please check Stop Control Register (SMC_STOPCTRL) [PSTOPO] bit setting, if it set to PSTOP2?

Wish it helps.

Have a great day,
Ma Hui

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[dominikf]

Hei Ma Hui,

thank you for the reply.

The mask set is 1N15J, but there is only three items in the errata, none of them related to sleep mode or UART.

There is however issues related to UART and sleep mode in the errata for mask sets 1N97F and 2N97F.

Can it be that these two mask sets share some of the issues?

We would like to use "STOP" mode, not "PSTOP2". When should we check this register? After we woke up from sleep mode?

Best regards,

Dominik

[jeremyzhou]

Hi dominikf,

According to the statement you shared in the previous replies, the KL16 failed to wake up, however it did work on the KL26.

And I'd like to confirm something with you.

1. In the Rev doc, the UART is not supported as a LLWU wake source, so I'd like to know how you configure the UART to wake up the MCU from the LLS mode.

2. I was wondering if you can share the code snippet of configuring the LLWU wake source

I'm looking to forward to your reply.
Have a great day,
Ping

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[dominikf]

Hei,

in the board layout we used UART_TX and have it not only connected to the UART input, but also to LLWU_P6. So it is the general LLWU pin that is used to wake up the MCU.

We worked around the issue of the scrambled UART data now by using WAIT instead of STOP while waiting for this data. It uses more power in this state, but fortunately in our case this case is rare. If one would depend on using the STOP state for power saving purposes and then read from the uart after waking up, then this would be a big issue.

Best regards,

Dominik

[jeremyzhou]

Hi Dominik，

Thank for your reply.

It sounds like a bug, and I'll check out issue.

If it happens just like as you described, I'll report this issue to AE team.
Have a great day,
Ping

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