DS90UB948-Q1: 948 Interface display black screen problem

Hi Loki,

I need more information about the issue:

- Can you please provide a detailed list of the actions you are doing in sequential order (when you power up the 947 and 948, when you run the initialization scripts for 947 and 948, and when and which device you PDB)? There may be a violation of the power sequence. 

loki zhang said:

fast power on and off

- Just to confirm, you PDB the 948? What is the reproduction rate of this phenomenon? 

Please note that the 947 must be sending valid video data before the 948 is powered up in our power sequence. Please refer to 9.1 on the 948 datasheet for the diagram and description.  

- Lastly, can you please provide a description of what the software configurations for the 947 and 948 are doing? 

BR,

Esther

Dear Esther：

   947 and 948 are powered on almost at the same time, and then soc is initialized first. After soc has stable output, 947 is initialized. After initialization, 947 will wait for 947 to lock to 948 before initializing 948. Is there a way for 947 to determine when to start sending valid data？

    After initializing 947, I tried to initialize 948 after delaying 48ms, but there was still a problem.

The configuration for 947 is as follows：

The first column represents the register, and the second column represents the value written into the register

0x03, 0xda  //open i2c path through

0x04, 0x90 // set DE mode

0x0D, 0x03 // gpio0 is configured for pass-through pwm

0x5b, 0x23 // Set to dual link

0x4f, 0x80 // set SPWG mapping

The configuration for 948 is as follows：

reg, data

0x05, 0x9e //open i2c path through all

0x1D, 0x05 // gpio0 is configured for pass-through pwm

0x1E, 0x90 // pull up gpio2

0x24, 0x00 // unuse

0x43, 0x00 // unuse

0x49, 0x60 // Set to dual link ouput

Hello, 

Monday 2/17 is a US public holiday, support will resume on Tuesday 2/18. Thanks for your patience. 

Regards, 

Logan