LP-MSPM0L2228: Sometime LCD example can't boot after power-on

Eric Chen

Intellectual 1910 points

Part Number: LP-MSPM0L2228

Tool/software:

Dear expert,

SDK version: mspm0_sdk_2_01_00_03

Example running from SDK without any modify: lcd_write_memory

User run with the LCD example from our SDK, and powered with XDS110 through USB cable.

Sometimes the LED4 will light up with light blue and the LCD won't work well,

and we have to trigger the reset buttom then it will work well.

If you can't duplicate this, you can remove the power and do this again until it is triggered.

I am thinking this may refer to the power sequence of LCD?

Best Regards,

Eric Chen

10 months ago

0 Xiaodong LI 10 months ago

TI__Mastermind 23065 points

Hi Eric

Yes. we can reproduce this issue (LED4 light) by remove and add BAT jumper (not every time).

it is not related with power sequence of LCD.

it may be related with power sequence between Vcc and Vbat.

we will review it in deep.

Thanks for your feedback!

0 Eric Chen 10 months ago in reply to Xiaodong LI

TI__Intellectual 1910 points

Dear Xiaodong,

If we want to fix this on the customer's side,

what would you suggest?

Best Regards,

Eric Chen

0 Xiaodong LI 10 months ago in reply to Eric Chen

TI__Mastermind 23065 points

Hi Eric

So far, I think we can check if the Jump on "BAT' is connected.

based on my test, if the jumper is always connected, this issue will not happen frequently

Thanks!

0 Eric Chen 10 months ago in reply to Xiaodong LI

TI__Intellectual 1910 points

Dear Xiaodong,

Do you mean the jumper from over here?

But it will trigger sometime,

if the customer wants to design the HW part,

they can't operate the MCU well.

When will be our plan to fix this?

Best Regards,

Eric Chen

0 Xiaodong LI 10 months ago in reply to Eric Chen

TI__Mastermind 23065 points

Hi Eric

>> Do you mean the jumper from over here?

Yes. This jumper.

>> But it will trigger sometime,

Could you please explain the usage case of this VBAT pin on customer sides?

>> When will be our plan to fix this?

we need time to check the root cause of this phenomenon

I will update the plan later.

Thanks!

0 Eric Chen 10 months ago in reply to Xiaodong LI

TI__Intellectual 1910 points

Dear Xiaodong,

Xiaodong LI said:
Could you please explain the usage case of this VBAT pin on customer sides?

They will need LCD as the screen on their power meter,

they don't need the Vbat function, but our HW request to connect this to VDD from Vbat, right?

Best Regards,

Eric Chen

0 Eric Chen 10 months ago in reply to Eric Chen

TI__Intellectual 1910 points

Xiaodong LI said:
>> When will be our plan to fix this?

we need time to check the root cause of this phenomenon

I will update the plan later.

By the way, Thanks!

Good to know that.

Best Regards,

Eric Chen

0 Eric Chen 10 months ago in reply to Eric Chen

TI__Intellectual 1910 points

Dear Xiaodong,

Do we have the way to solve this?

Otherwise the customer can't design the schematic.

Best Regards,

Eric Chen

0 Xiaodong LI 10 months ago in reply to Eric Chen

TI__Mastermind 23065 points

Hi Eric

Thanks for your phone discussion yesterday.

based on the description on 8.4.1 Startup When VBAT Powers on First and 8.4.2 Startup when VDD powers on first on MSPM0 L-Series 32-MHz Microcontrollers Technical Reference Manual

I think we can try to make sure "startup when VDD powers on first"

So far, user connect VDD and VBAT directly. the voltage supply is from VDD to VBAT.

we can try to add 1uF to 1uF bypass Capacitor on the connection. (refer to CVBAT of MSPM0L222x, MSPM0L122x Mixed-Signal Microcontrollers datasheet)

I think this issue can be solved by bypass Capacitor

Thanks!

0 Eric Chen 10 months ago in reply to Xiaodong LI

TI__Intellectual 1910 points

Dear Xiadong,

Do you mean to add the 1uF cap between VDD and Vbat?

Does that work from your end?

I saw there is already 1uF cap on the Vbat pin.

Best Regards,

Eric Chen

0 Xiaodong LI 9 months ago in reply to Eric Chen

TI__Mastermind 23065 points

Hi Eric

As our discussion on telephone. This issue investigation is still on-going. I will follow up and feedback to you once there is the updated.

I will close this thread and let's discuss this topical offline.

Thanks

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LP-MSPM0L2228: Sometime LCD example can't boot after power-on