Part Number: TMDS181
My customer is using TMDS181 and found some issues.
TMDS181 is used for HDMI OUT output, issues are:
During the debug process, customer found that:
Based on above info, Could you help confirm the following two questions:
Can you share their schematic for review?
Do you have I2C access to the TMDS181 so you can dump out the TMDS181 registers for both the working and the non-working case?
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 David (ASIC) Liu:
The attachment is the schematic diagram and register data, please check.
The register data of TMDS181 chip, in the two cases, looks the same.
In reply to user6468935:
I don't see the TMDS181 register dump data, would you please attach the data to the e2e ticket?
In particular please check the TMDS_CLOCK_RATIO_STATUS bit field in register 0x0Bh. This field is updated from snoop of DDC write to slave address 0xA8 offset 0x20 bit 1 that occurred on the SDA_SRC/SCL_SRC interface. When bit 1 of address 0xA8 offset 0x20 in the SCDC register set is written to a 1’b1, then this field will be set to a 1’b1. When bit 1 of address 0xA8 offset 0x20 is written to a 1’b0, then this field will be set to a 1’b0. This field is reset to default value whenever HPD_SNK is de-asserted for greater than 2 ms.
0 – TMDS Clock is 1/10 of TMDS bit period (default) -> HDMI1.4
1 – TMDS Clock is 1/40 of TMDS bit period -> HDMI2.0
Can you also probe the clock output? You should see 300MHz for HDM1.4 and 150MHz for HDMI2.0.
Dumped register and schematic are shown below. thanks.
TMDS181 registers data.txt
In reply to Yang Wu:
Can you measure the TMDS181 clock output in both the passing and the abnormal case?
Yes, the clock output is 148.5MHz, but I did not save the picture.
I will ask Wu Yang to schedule a call with you on this particular issue.
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.