KW45 NBU stops working after XTAL shortage

[sshrivastava]

Hi All,

We are using KW45 in our project. During ESD testing we observed problems that sometimes the BLE communication stops working.

To check the error handling we shortcuted the 32 MHz XTAL. After the shortage was applied (and removed), the BLE stops working every time. Sometimes also the system completely crashes and the program counter is waiting at 0x14816FDC. From power consumption the NBU also seems not to enter low power state.

Question:

• is there a way to re-initialize the NBU without performing an complete MCU reset?
• What kind of error handling can be done?

KW45 

[nxf77486]

Hello,

Thank you for contacting NXP support.

I appreciate the information, but can you please help me with some extra details:

• Are you currently working with a custom board or is this an EVK?
• Are you using an specific example form the SDK for your ESD testing? Also please let me know if you performed any change on the example (if this is the case).
• If you don’t shortcut the 32MHz XTAL the BLE does not fail as often.

It is possible to send some sniffer images about this behavior?

[sshrivastava]

Hi @nxf77486 ,

We are working on an custom board, but we could now reproduce the failure also with the EVK.

If we run the digital key car anchor project on EVK and shortcut Y1 (R40) to GND than the BLE advertisement stops and does not recover once the shortage is removed. We are using SDK_2_12_7 and kw45b41_nbu_ble_1_9_12_3 for NBU.

If you don’t shortcut the 32MHz XTAL the BLE does not fail as often.

• Yes the connection stays stable. Only during ESD and Vehicle testing we can observe that sometimes the BLE functionality get's lost.  If we run it "static" the failure did not occurred over months. That's why we are now checking how the system reacts on failures.

[nxf77486]

Hello,

I appreciate the information.

As far as I understand for the ESD testing you require the shortcut. Im currently not able to reproduce this test case in specific. But we can go on with the following recommendations:

1. Please upgrade the SDK you are currently using.
2. Update the NBU firmware also in your board.

Is this testing require for a certification?