DS90UB949-Q1: Screen Displays Vertical Lines
Part Number: DS90UB949-Q1
I'm back in the office now so I have access to my setup. I don't have access to the I2C bus on the deserializer side since it's part of the customer module, so in order to run the BIST I substituded the DS90UB948 EVM and Analog Launchpad software. The procedure was as follows:
1. In ALP, set Deserializer register 0x24 to 0x01 (Enable BIST)2. The orange LED on the EVM (connected to the PASS pin) lights up3. After BIST has run for several seconds, set Deserializer register 0x24 to 0x00 (Disable BIST)4. The orange LED turns off, indicating that at least one error occurred during BIST5. Read Deserializer register 0x25 (BIST Error Count). Register value is zero, which contradicts the low PASS pin.6. In ALP Remote Registers tab, read Serializer register 0x1B. Register value is 0x04.
I'm not really sure how to interpret this data. The BIST Error Count register is zero, so does that mean the FPD-Link III signal integrity is ok? Why is the PASS pin going low after the BIST if there were no errors? Is this due to the back channel errors? I'd appreciate some guidance from TI.Thanks,Josh
What clock source are you using for BIST? Also is the serializer receiving PCLK from the video source during this testing?
We are glad that we were able to resolve this issue, and will now proceed to close this thread.
If you have further questions related to this thread, you may click "Ask a related question" below. The newly created question will be automatically linked to this question.
In reply to Casey McCrea:
The BIST Clock source bits are 00, so that means the BIST clock source should be the external pixel clock, right? In the information tab (under normal operation), the deserializer pixel clock is hovering around 70 MHz while the serializer pixel clock is around 75 MHz, as shown:
When BIST is enabled, the deserializer information remains the same while the serializer Pixel Clock is listed as "20-85 MHz" as shown:
In reply to Joshua Dunn55:
Thank you for reaching out to us. Can you please confirm if you are using 949 to 948 EVM? If yes, are you connecting both EVMs on the same bus? Or you are connecting to separate bus.
In reply to Aaron Heng:
This post was meant to be a continuation of the previous thread, which was locked due to inactivity because I could not access my setup due to COVID. During that thread, it was determined that the problem I was experiencing seemed like a signal integrity issue. To check whether the problem was on the HDMI or the FPD-Link side, I needed to run a BIST on the serdes link. I am using a custom PCB for the 949 serializer, and a 948 EVM on the deserializer side for the purposes of running the BIST.
When you run the BIST mode, did you run locally or remotely?
The ALP software is talking to the Deserializer EVM. I enabled the BIST by setting the BIST_EN bit in Deserializer Register 0x24 in the ALP "Registers" tab. I think that means I ran it locally, right? Since I enabled it by writing to a local register?
Thank you for the confirmation. When you are reading the BIST error and monitor the pass status indicator, do you know which PORT you setting or monitoring to? Can you please read the register 0x34? Thanks.
Register 0x34 is reading as 0x01. However, I've tried switching between reading port 0 and port 1 using the PORT0_SEL and PORT1_SEL bits, and the BIST error count register reads zero in either case.
1. Anyway you can get us a timing scope shot? Is the PASS pin going low at the point BISTEN is being transitioned low? Or do you see the PASS pin low all the time after BIST is enabled? Do you also see any CRC errors
All content and materials on this site are provided "as is". TI and its respective suppliers and providers of content make no representations about the suitability of these materials for any purpose and disclaim all warranties and conditions with regard to these materials, including but not limited to all implied warranties and conditions of merchantability, fitness for a particular purpose, title and non-infringement of any third party intellectual property right. No license, either express or implied, by estoppel or otherwise, is granted by TI. Use of the information on this site may require a license from a third party, or a license from TI.
TI is a global semiconductor design and manufacturing company. Innovate with 100,000+ analog ICs andembedded processors, along with software, tools and the industry’s largest sales/support staff.