AM4378: In the AM437x and TPS65218 system, the DCDC2 waveform oscillates.

dai_sakamoto

Part Number: AM4378
Other Parts Discussed in Thread: TPS65218

Tool/software:

This is a continuation of the thread below. I'm asking again because it turned out to be a software problem, not a hardware problem.

https://e2e.ti.com/support/power-management-group/power-management/f/power-management-forum/1475652/tps65218-in-the-am437x-and-tps65218-system-the-dcdc2-waveform-oscillates/5685984?tisearch=e2e-quicksearch&keymatch=tps65218#5685984

I was told to contact the AM4378BZDNA100 team, so I asked again.

PMIC:TPS65218B1RSLT

CPU:AM4378BZDNA100

I have changed the voltage values in the u-boot and linux DTS files and am currently experimenting.
Are there any other files or items that could be causing this?

*min ... regurator-min-microvolt

*max... regurator-max-microvolt

6 months ago

0 Hong Guan64 6 months ago

TI__Guru 68430 points

The diagram looks like indicating the Linux SDK with u-boot 2016.05 is used, is my understanding correct?
1/. Will you describe the issue in more details?
2/. Is the issue observed previously or just now?
I'd want to let you know that supporting u-boot 2016.5 would be limited by TI.
Best,
-Hong

0 dai_sakamoto 6 months ago in reply to Hong Guan64

Intellectual 330 points

1...As stated in "After startup (1 minute or more)" in the URL, DCDC2 will oscillate in a steady state. The oscillating voltage is between 0.95 and 1.35V.

2...yes

＝＝＝＝＝uboot Latest git log git log=====

xxxxx@xxxxx-Vostro-230:/opt/ti-processor-sdk-linux-NBC-ver3/board-support/u-boot-2016.05_NBC$ git log

commit 4d20f09e4c4ebf7729a5513cc85f78811f534694
Author: Texas Instruments SDK Builder <>
Date: Wed Dec 14 19:23:32 2016 -0500

Create local branch

The below commit is used for this local branch and is the one used by
this sdk:
6c5519b6fc09274d28d653a9a3cabf7dc74883ca.

=======================

0 Hong Guan64 6 months ago in reply to dai_sakamoto

TI__Guru 68430 points

Please refer to the e2e posts on how VDD_MPU/VDD_CORE are configued in u-boot and kernel.
https://e2e.ti.com/support/processors-group/processors/f/processors-forum/1103023/am3352-how-to-reflect-device-tree-tps65910-regulator-settings/4093644#4093644
https://e2e.ti.com/support/processors-group/processors/f/processors-forum/983974/am3356-how-to-change-cpu-freq-on-demand
Best,
-Hong

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AM4378: In the AM437x and TPS65218 system, the DCDC2 waveform oscillates.