Hello,
I have drawn and layoutet a HDMI connector onto a custom board, and I took the SINTF hardware documentation as template.
On SINTF, HDMI is working, but not on my custom board. I took another look at the documentation and realized, there exists a HDMI_DDCCEC_AUX_P pin (J24 plug). This one is not shown on J6 plug. Do we need it?
I have attached the layout and schematic of my custom PCB. Pin 154 is connected to GND while 156 is the HDMI_DDCCEC_AUX_N signal.
Thanks!
Hello,
because of older posts, i assume you are using an efus-SINT in combination with an efusA9r2?
Pin 154 on the efusA9r2 is not connected. A connection to GND on your design should not affect the functionality.
HDMI_DDCCEC_AUX_P is the signal connected to pin 154 on the efus-SINTF. It is not available at the efusA9r2 and is not needed.
I could not see any issue in the attached schematic, but i have some suggestions for improvements for your layout.
Your HDMI data signals have different track widths. Because of that, i assume there is no imedance control on these signals.
Also the the *_P and *_N labled signals are differential, and should be routed in this way. It looks like you routed them single ended.
The differntial impedance for HDMI video and clock signals is 100 Ohm +/-15%.
Non-compliance does not necessarily lead to a failure of the function, but can have a negative influence on the signal quality (poor image) and has a negative effect on the EMC behavior.
Please duble check that all parts in line with the HDMI connector are working as expected. It could be a idea to remove all TVS diodes and common mode chokes and bridge the chokes with a little wire over the pads. These filter elements are for EMC purposes and only neccassary when you have problem with the EMC.
If the parts and footprints on the PCB are used for the 1st time also check, if the footprints are correct and the pads are not interchanged.
Your F&S Support Team
Yes, you are correct, I use an eFusa9r2. I accidently posted into armstone, sorry.
I will have a look, thanks for your suggestions!
I use I2C_C for the SGTL5000 audio codec, and my layout also used I2C_C for the HDMI EDID (SDA,SLC), may this cause the issue of a nun.functional HMDI output? Is there a pinmux for this?
Hello,
the efus-STINF also uses I2C_C for the SGTL5000 and EDID, so it should be fine.
Your F&S Support Team
Hi,
I indeed used the wrong chokes. The chokes Murata DLP11S need to be used, as stated in your HW documentation.
After removing them, the HDMI works.
Here is a good overview about using chokes in high speed differential layouts: consumer-signal
I will rework my layout.
Thanks. Topic closed.
