TPS65987DDKEVM: The HPD is unable to function properly，cannot detect the mode of pin assignment E.

Hello,

chaocong zhao said:

1. The problem of GPIO/HPD not outputting normally. Is this related to the GUI version? Could you provide me with the latest version?

Others have had success (see threads below), so i would not suspect the GUI as the issue.  I cannot provide access to alternate tools, so you would need to work with your local TI sales representative to gain access.  Please be advised that this device is not recommended for new designs and access to additional information may be limited.

chaocong zhao said:

2. When using the C-DP cable to connect the sink, the EVM, as the source, cannot normally recognize the pin assignment E mode. How should I configure it? Could you please explain?

Please see the attached discussions.

https://e2e.ti.com/support/power-management-group/power-management/f/power-management-forum/1449145/tps65987d-tusb1146-dp-alt-mode-not-driving-hpd-high

https://e2e.ti.com/support/power-management-group/power-management/f/power-management-forum/1497385/tps65987ddk-hpd-assertion-issue/5816726#5816726

chaocong zhao said:

I need a configuration that can use GPIO0/1/2 as the DP/USB status output, GPIO3 as HPD, and be able to recognize the C, D, and E modes. Could you please provide a project as a future research direction?

I would recommend following the TUSB1146EVM.

https://www.ti.com/lit/ug/sllu318/sllu318.pdf#page=8

Regards,

Chris

Hi Chris，

Chris Sterzik said:

Please see the attached discussions.

https://e2e.ti.com/support/power-management-group/power-management/f/power-management-forum/1449145/tps65987d-tusb1146-dp-alt-mode-not-driving-hpd-high

https://e2e.ti.com/support/power-management-group/power-management/f/power-management-forum/1497385/tps65987ddk-hpd-assertion-issue/5816726#5816726

Regarding the issue described in the link:

 https://e2e.ti.com/support/power-management-group/power-management/f/power-management-forum/1449145/tps65987d-tusb1146-dp-alt-mode-not-driving-hpd-high

 this was resolved by the firmware in the DH section. I can confirm we are using the firmware from the DDK.

Regarding the issue described in the link:

https://e2e.ti.com/support/power-management-group/power-management/f/power-management-forum/1497385/tps65987ddk-hpd-assertion-issue/5816726#5816726

Even after applying the PTJ (Pre-configured Technical Journey) project from your provided link with TBT mode disabled, I still cannot get GPIO3/HPD to pull high upon connection. Reading register 0x5f: 0x100571 – it now appears HPD functionality is completely inactive.

Chris Sterzik said:

I would recommend following the TUSB1146EVM.

I am using a TPS65987DDK + TMUXHS4446 combo configuration, with the connection diagram shown below.

In my custom project with the configuration shown in the attached image, after connecting the display monitor, reading register 0x5f:0x8531 indicates that HPD status is high. However, GPIO3 remains unasserted (not pulled high).

TPS65987_USB+DP_HPD issue.pjt

Could you please offer some suggestions?

Thank You！

Hi Chris，

Update:

I have completed the debugging of the configuration for pin assignment E on my end. However, for the output of HPD (GPIO3), when the signal is high at 0x5f, it still remains at a low level.

Could you please offer some suggestions?

Thank You！！

Hello,

I will continue to investigate.  I did make a minor modification to the project.

/cfs-file/__key/communityserver-discussions-components-files/196/TPS65987_5F00_USB_2B00_DP_5F00_HPD_5F00_issue_5F00_withBase.pjt

Regards,

Chris

Hi Chris,

Currently, the behavior with the new firmware appears identical to previous observations: Register 0x5f = 0x8531 shows HPD status bit set to 1, but GPIO3 remains at logic low (0V).

Q: Is the HPD functionality in this chip bidirectional in terms of data flow? I noticed the EVM board marks the data flow direction as "in", but my requirement is for the PD controller to parse HPD and then output a high-level signal externally through GPIO3.

Hi Christopher,

I see! I just measured pin J2 and confirmed it outputs 3.3V in Alt Mode but drops to 0V in USB mode.

Could you please provide the J2 pinout/signal mapping for further verification?

Thank you both for your patient guidance!