4.3.2. FPGA RX Settings
You must use a redriver on the PCB panel to ensure compliance to RX CTS and HDMI 2.1 cable loss. Intel products do not support non-compliant cables. The equalization is dependent on overall system reach design; in a typical scenario, 16 dB is sufficient, while longer traces on larger PCB panels require higher equalization.
You can use flex cables instead of a large PCB panel for a better cost-to-performance ratio. Use link training methodology to evaluate if such cables match your setup. Validation setup uses generic jitter tolerance methodology to meet HDMI 2.1 CTS requirements.
Insertion Loss : 20.11 dB | ||||
---|---|---|---|---|
Spec | Calibrated | |||
Amplitude | 800-1200 mV | - | ||
RJ | 0.2 UI | 1.31 ps | 1.224 ps | 0.12 UI |
DJ | 0.35 UI | 29.2 ps | - | - |
BUJ | 0.15 UI | 12.5 ps | 12 ps | 0.12 UI |
SJ/PJ | 0.1 UI | 8.33 ps | 9.33 ps | 0.1 UI |
Eye Height | 100 mV | - | 97.1 mV | |
Eye Weight | 29.17 ps | - | 31.5 ps |
The jitter (BUJ) interpretation varies. Focus on the entire system level with all components account for 1 UI budget. HDMI.org provides WCM cable that shows the cable loss parameter. The stressed signal feeds into RX to establish jitter tolerance. The following table lists the recommended settings:
Component | Intel® Arria® 10 FPGA | Redriver (TI DS125MB203) |
|
---|---|---|---|
Adaptation Mode | Manual CTLE, TX FFE | EQ | DeEmp VOD |
VGA Gain | 2 | - | - |
DC Gain | 1 | - | - |
AC Gain | 3 | Level4 | Level 0-2 |
Vpp Amplitude | - | - | 0.8 |
Do note that a 2 UI TX length at 6 Gbps at Test Point 1 is a mandate by HDMI 2.1 CTS.
All settings listed in this document are available in Intel® Quartus® Prime. You can update the settings to reflect the need of each design requirements as well as loss factor.
To mitigate variability in customer loss profiles:
- Isolate and confirm that the root cause is the transceiver link.
- Apply link tuning methodology.
- Refer TTK (transceiver toolkit):
- Evaluate link stability and robustness by sweeping transceiver analog settings (for loss profiles beyond nominal cases).
- Find the optimal RX analog settings with TTK.
- Apply static values in the QSF file.