We have used iMX8MQ processor on our custom board design. Currently going through a compliance testing.
HDMI is giving a hard time to qualify the EMC certifications. Find attached image showing the results of radiated emission scan of our custom board with 1080p HDMI display.
- We followed all guidelines provided in Hardware design guide for iMX8M.
- The intra & inter pair for HDMI traces are 5 mil & 20 mils.
- Impedance controlled to 100 ohm differential for all HDMI signals
- Routed in internal layer with continuous ground plane reference
- Added ground via close to differential signal vias
- Used EMI filter near to HDMI connector
We explored & came across few parameters which can help to get reduce the radiated emissions above, those are:
Slew rate, Voltage Swing, Drive strength and terminations.
Want to know where we can tune above parameters using register settings in iMX8M.
Any help here would be greatly appreciated.