Part Number:TPS65987D
Hi, I'm an engineer of laptop PC product. Please call me Takki.
Now my team are working on products using TPS65987DDH.
Application customization tool is ver5.1.
Some our products support USB Gen2 and TBT3, and others support USB Gen1 and DP alt Mode.
We realized that when we connect ELECOM Type C-DP adapter(AD-CDPBK) to our products, video output success-or-fail is depend on the settings in DisplayPort Capabilities[0x51] bit 10 and 11.
DisplayPort Capabilities[0x51] bit 10=Supports DP v1.3 signaling
DisplayPort Capabilities[0x51] bit 11=Supports USB Gen 2 signaling
After "Enter Mode", DFP(TPS65987) sends "DP Configure Message".
Then, UFP returns "DP Configure ACK Message".
"DP Configure Message" contains DP v1.3 bit and USB Gen2 Signal bit, and the status of each bit is just the same as the settings in DisplayPort Capabilities[0x51] bit 10 and 11.
According to the settings, the video output success-or-fail will change.
Please see the table bellow.
| Supports Gen2 Signaling check box F/W 0x51 [11] | Supports DP v1.3 Signaling check box F/W 0x51 [10] | Gen2 : DP v1.3 bit status in "DP Configure Message" from DFP(TPS65987) | Output Result |
Pattern1 | レ | レ | 1:01 | DP Output NG |
Pattern2 | レ | | 1:00 | DP Output NG |
Pattern3 | | レ | 0:01 | DP Output OK |
Pattern4 | | | 0:00 | DP Output NG |
When the output succeeds, UFP(AD-CDPBK) returns ACK as a "DP Configure ACK Message" .
When the output fails, UFP(AD-CDPBK) returns NAK as a "DP Configure ACK Message", and DFP(TPS65987) issues "Exit Mode", and then alternate mode is ended.
Now we are thinking about changing the setting of DP capabilities [0x51] bit 10 and 11 so that AD-CDPBK can output images.
But we have some questions.
1. What are the influences if the USB Gen2 bit in 0x51 is un-checked.
(If we use USB Gen2 device without DP alt mode, is this bit ignored?)
(If we use USB Gen2 device with DP alt mode, is the speed limited to Gen1?)
2.DFP(TPS65987) set the DP v1.3 bit and USB Gen2 Signal bit in "DP Configure message" according to DisplayPort Capabilities[0x51] bit 10 and 11. Is it appropreate behavior as DFP?
(DFP could know the capabilities of UFP device by receiving "Discover Mode ACK message", so we think these bits may need to be changed to the current available sigals.)
Besides, if you know, please answer the bellow question.
3. ELECOM AD-CDPBK return NAK when the "DP Configure message" is defferent from its expectaion. Is it appropreate behavior as UFP?
Now, we will soon have to take TBT3 compliance test. After the test, we cannot change our TPS65987 F/W images.
So please reply as soon as possible. I will contact TI Japanese sales team.
Thank you