J6PEVM577P: FPD Link 3 output not working on Android

AClemotte

Part Number: J6PEVM577P
Other Parts Discussed in Thread: DS90UB949-Q1

Hi,

We have the J6+ EVM J6PEVM577P with the FPDL3 display (TI PN EVM5777LCDTS-V4-0). We've flash the Prebuilt Release Image for Android and connected to the FPDL3 display but nothing is displayed. The HDMI output is working correctly. The 6AO.1.1 Application Notes point out that the dra76-evm.dtb is used for this image. I suspect that the dra76-evm-fpd-auo-g101evn01.0.dtb (J6 Plus EVM) should be used insted.

Is my hypotesis correct? How this change should be done?

Regards,

over 6 years ago

0 KB over 6 years ago

TI__Guru** 120741 points

Hi,

Your hypothesis is correct. The dtb needs to be updated, as by default the dtb that is flashed is for HDMI. The below command can be used to update the dtb.

fastboot flash environment dra76-evm-fpd-auo-g101evn01.0.dtb

Regards,

0 AClemotte over 6 years ago in reply to KB

Expert 1060 points

We've done what KB point out, but nothing change, we're not able to see anything on our FPDL3 display.

We're powering the display by the FPDL3.

With a multimeter I have measured the voltages in the test point on the back PCB of the screen. I have seen that:
TP29 = 5V
TP11 = 0V

The backlight of the screen is powered by the U8 LM2735XSD / NOPB controller that should convert 5V to 10V. TP29 is the supply voltage of the screen, which must be between 5.5V and 12V. TP11 is the enabler of the regulator, which according to how it is now, is disabled. The TP11 is connected to pin 14 of the deserializador DS90UB924.

- The value of TP11 should be high no?
- If it should be high, how do we change the value of the GPIO that controls this voltage?
- If it should be high, why is it low?

Regards,

0 AClemotte over 6 years ago in reply to AClemotte

Expert 1060 points

More data (always related to the FPDL3 display):

- TP8 = 3V3

- TP10 = 3V3

0 Pial over 6 years ago in reply to AClemotte

TI__Expert 7280 points

Hello Alejandro,

Thank you for measuring TP8 voltage on the display board (http://www.ti.com/lit/df/sprr377/sprr377.pdf), it confirms that the FPD Link communication is established.

TP29 = 5V is to be expected since the boost converter is not enabled (Vout = Vin-Vf from the rectifier diode)

VCC_LED_EN should be high, it is coming from a DS90UB924Q-Q1 GPIO.

Looking at the J6PEVM577P board schematic (http://www.ti.com/lit/df/sprr314/sprr314.pdf) I noticed that none of the GPIOs of the serializer (DS90UB949-Q1) was connected. It means that the remote DS90UB924Q-Q1 GPIO must be driven high by an I2C command.

Next step would be to understand how the software is handling DS90UB949-Q1 in order to drive the remote GPIO high.

@KB: can you help regarding that last point ?

Best regards,

0 Piyali Goswami over 6 years ago in reply to Pial

TI__Mastermind 30245 points

Quick update on this one:

The team would try and set up an EVM with Android and check the FPDLink Display.

Thanks and Regards,

Piyali

0 AClemotte over 6 years ago in reply to Piyali Goswami

Expert 1060 points

Hi, do you have any news about this?

0 KB over 6 years ago in reply to AClemotte

TI__Guru** 120741 points

Hi,

We're in the process of finding a H/W setup to test this on.

Expectation is that flashing the dra76-evm-fpd-auo-g101evn01.0.dtb file, with the Android 6AO.1.1 release, will provide support for the FPDLink display.

Regards,

0 Vishal Mahaveer over 6 years ago in reply to KB

TI__Mastermind 33390 points

Hi,

With 6AO.1.1 on dra76 EVM we see the same behavior, Android UI is not coming up on the FPDLink display.

6AO.1.1 + FPDLink display is functional on J6 EVM.

Regards,
Vishal

0 Vishal Mahaveer over 6 years ago in reply to Vishal Mahaveer

TI__Mastermind 33390 points

Hi,

Please note that there is a Hardware mod needed for J6 Plus EVM. Please check the link below for details..

http://processors.wiki.ti.com/index.php?title=Processor_SDK_Linux_Automotive_Software_Developers_Guide&oldid=225388#HW_Modifications_required

Regards,
Vishal

0 Vishal Mahaveer over 6 years ago in reply to Vishal Mahaveer

TI__Mastermind 33390 points

The above H/W mod is needed only if you have Rev-B or older version of EVM. The version of EVM is mentioned on the board.

If you have Rev-C, then an additional i2c command is needed to enable the FPDLink display clock. The i2c command basically sets correct value to enable the clock in CDC device present on the EVM.

i2cset 0 0x65 0x82 0x9c

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J6PEVM577P: FPD Link 3 output not working on Android