CC2541: CC2541F256 Field Issue

Hi,

Thank you for reaching out,

I need more inputs to help you with this, are you using a TI example? What is the SDK used for this one?

What the customer is trying to do? Did he have any issues on the code itself? Are you using directly the BIM.bin file?

regards,

Hi Guilaume,

The SDK version used by the customer is BLE-CC254x-1.4.2.2.

Final firmware file is generated by merging BIM.bin, OADBoot.bin, and RemoteImgB.bin.

merge_FW_new(PW1234).zip

When I checked the defective field product, the BIM area was erased, and I don't know how it was erased.

What issues can cause BIM to be erased from the TI Flash source?

Is it a problem with SDK version that the BIN is erased?

Hi,

It is very difficult to pin-point a specific cause for why the BIM area may have been changed to 0xff. Can you describe the general environment and use-case of the product? This may provide us with some additional hints as to what may have caused a portion of flash to be erased.

Best Regards,

Jan

Hi Jan,

It is assumed that the end user used it as below.

1. Pairing after installing the first STB and RCU.

2. Since there are signs of mechanical use, BLE Reconnect proceeds during use, and occurs during use by the customer

Customer questions : 

1. What are the conditions under which BIM areas can be changed in User APP?

2. What conditions can BIM be changed during the OTA scenario?

Hi,

As stated in the Developer’s Guide for Over Air Download for CC254x (Found in {SDK_INSTALL_DIR}/Documents/Over_the_Air_Download_for_CC254x.pdf) section 8.3.3 Images A and B, shown below, the BIM shouldn't be modifiable during standard OAD operation.

Some more information can be found in section 10 Producing an Image-A & Image-B, shown below, that clarifies that the BIM is only flashed once during the device's lifetime and to reflash it you would need to physical connect to the device:

During your application's execution, are you writing to flash or doing any flash writes?

Best Regards,

Jan

Hi Jan,

The conditions for using FLASH during APP execution are PAIRING and OAD.

Both conditions use the BLE-CC254x-1.4.2.2 SDK without any changes.

There is no history of changes since the first release of the remote controller firmware.

So it is assumed that OAD was not executed.

The customer is waiting for TI's opinion.

Hi,

Understood, can you provide a bit more information as to what was happening when the issue was discovered? Was an OAD update being performed or had been attempted prior to the issue arising? If so, then could you share the OAD image header contents of the image that was being used to update the device? I am trying to check if something could have gone wrong during the actual OAD update.

Best Regards,

Jan

Hi,

You may also find the following E2E thread helpful as it contains some information about what may cause a BIM corruption and how to guard against it: https://e2e.ti.com/support/wireless-connectivity/bluetooth-group/bluetooth/f/bluetooth-forum/507303/cc2540-bim-corruption

Best Regards,

Jan

I am too experiencing rare page 0 (BIM) erased in the field when the end user tries to start OAD. The device becomes inoperable and can be put to life by reprogramming via cable only. The write protect was programmed via LP(0-7), but this did not help to mitigate the issue. I could not reproduce this issue in the lab, it happens randomly in the field. The write protect seems not be a reliable solution to this issue.

Hi Kai,

Thanks for sharing! How frequently do you see the issues? In other words, how many units are out in the field and how many have been reported to suffer from the issue you are describing?

Best Regards,

Jan

Hi Jan,

I'm sorry, the customer's reply to using OAD is late.

The customer did not use OAD.

There is a return rate of 1 to 2 %. However I cannot pin point exactly the page 0 issue since the devices are locked. When erasing and reprogramming the devices work normally. We started to deploy new devices without locking in order to verify the issue. The loop before those devices could come back is expected to be rather long (> 3 months).

Our OAD process uses always a fixed Image A, since we have an asymmetrical size of A and B. The dead devices do not start anymore.

When testing and exercising page erase-write cycles and simulating power failures we can see that sometimes page 0 gets accidentally erased. Write lock page 0 had no effect. As a measure against power failure we added 330 uF on the 3.3V supply (we use fixed 3.3V since we run from a big battery bank) and observe VCC with the ADC, allowing only page erase- write when the measured voltage is > 3V. This should buy us some time:

Voltage drop margin: 1V, write current 20mA

1V * 330 uF / 20 mA = 16.5 ms 

So far we have no proven results if this lowers the field returns. 

Hi,

No worries for the late reply. I see, the test results you have provided seem to indicate there is possibly a HW factor that may be causing this issue. Have you submitted your design for a hardware design review at: https://www.ti.com/tool/SIMPLELINK-2-4GHZ-DESIGN-REVIEWS ?

Best Regards,

Jan

Hi Jan,

Kai's question is not related to the issue I started.

Kai,

Please create a new question.

We are confused.

Hi CHO SR,

My apologies, I was not aware that the issues were not related. My apologies for any confusion this may have caused.

CHO SR said:

The customer did not use OAD.

Do you mean the application does not contain OAD at all or that the behavior did not arise during an OAD operation? Did you take a look at the following E2E thread? https://e2e.ti.com/support/wireless-connectivity/bluetooth-group/bluetooth/f/bluetooth-forum/507303/cc2540-bim-corruption

Let me know if it provided any helpful information or not.

Kai, 

My apologies to you as well for any confusion on your end. Feel free to open a new E2E thread related to the issue you are facing and we would be more than happy to support you on that thread.

Best Regards,

Jan

Hi Jan,

The application contains OAD.

However, they told me that no new firmware has been released and that they have not run OAD operations.

I think the remote control user might have activated OAD without new firmware.

If OAD is used without release firmware, will the BIM be subject to change?

The E2E thread you shared was helpful.

Hi,

Thank you for the information! I am glad the E2E thread was helpful. Does your code have any checks to verify if there is a proper image available to send via OAD before the transmission starts or does the transmission start right after the user activates OAD?

Best Regards,

Jan

Hi,

Check the load callback for both cases and update the new image.

1. Check OAD_BOOT_UUID

2. If the new image version is larger than the existing remote control version

Hi,

Do you have a case if the image version is non-existent or corrupted?

Best Regards,

Jan

Hi Jan,

The customer did not update the new firmware.

So there is no new image, so there is no damage.

Hi,

Understood. If there are checks to ensure no OAD occurs if there is no OAD image present, then I think there should be no reason for the BIM to update. However, if no checks are made, then it is possible that some unexpected behavior may happen.

Best Regards,

Jan

Hi Jan,

Sorry, I'm late because of my vacation.

As a result of checking the customer's OAD scenario, it doesn't seem to be an OAD error.

Are there any more suspected conditions for BIM to change?