LVDS2HD: Difference between revisions

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<mark>3.</mark> If D2 fails to light up and there’s no HDMI output after power-on, the possible causes are:

(1)Incorrect single/dual-channel configuration (R20);

(1) Incorrect single/dual-channel configuration (R20);

(2)Mismatched LVDS wire sequence;

(2) Mismatched LVDS wire sequence;

(3)Short-circuit R21 and retest (for VESA/JEIDA mapping);

(3) Short-circuit R21 and retest (for VESA/JEIDA mapping);

(4)Differential pair polarity (+/−) reversed (Fix: First swap only O2+/O2− and OCLK+/OCLK−. If D2 lights up after swapping, polarity is correct; then swap all remaining twisted pairs).

(4) Differential pair polarity (+/−) reversed (Fix: First swap only O2+/O2− and OCLK+/OCLK−. If D2 lights up after swapping, polarity is correct; then swap all remaining twisted pairs).

'''Double-check to ensure correct wiring and configurations.'''

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'''If the debug print scrolls continuously, the cause is definitely unstable LVDS signals''', resulting in changes to the 5 parameters shown above:

(1)Ensure LVDS differential pairs use twisted pairs and are free from interference.

(1) Ensure LVDS differential pairs use twisted pairs and are free from interference.

(2)If InputPclk fluctuates, check if SSC (Spread Spectrum Clocking) is enabled; disable it for testing if possible.

(2) If InputPclk fluctuates, check if SSC (Spread Spectrum Clocking) is enabled; disable it for testing if possible.

(3)If HTotal or VTotal fluctuates, check the synchronization mode in software settings (usually Freerun or FrameLock). For LVDS-to-HDMI output, the mode must be Freerun with fixed HTotal/VTotal. For direct LVDS display, HTotal/VTotal may vary within a limited range without affecting the image. Thus, LVDS working for direct display does not guarantee valid LVDS-to-HDMI output.

(3) If HTotal or VTotal fluctuates, check the synchronization mode in software settings (usually Freerun or FrameLock). For LVDS-to-HDMI output, the mode must be Freerun with fixed HTotal/VTotal. For direct LVDS display, HTotal/VTotal may vary within a limited range without affecting the image. Thus, LVDS working for direct display does not guarantee valid LVDS-to-HDMI output.

@@ Line 55: / Line 55: @@
 <mark>3.</mark> If D2 fails to light up and there’s no HDMI output after power-on, the possible causes are:
-(1)Incorrect single/dual-channel configuration (R20);
+(1) Incorrect single/dual-channel configuration (R20);
-(2)Mismatched LVDS wire sequence;
+(2) Mismatched LVDS wire sequence;
-(3)Short-circuit R21 and retest (for VESA/JEIDA mapping);
+(3) Short-circuit R21 and retest (for VESA/JEIDA mapping);
-(4)Differential pair polarity (+/−) reversed (Fix: First swap only O2+/O2− and OCLK+/OCLK−. If D2 lights up after swapping, polarity is correct; then swap all remaining twisted pairs).
+(4) Differential pair polarity (+/−) reversed (Fix: First swap only O2+/O2− and OCLK+/OCLK−. If D2 lights up after swapping, polarity is correct; then swap all remaining twisted pairs).
 '''Double-check to ensure correct wiring and configurations.'''
@@ Line 81: / Line 81: @@
 '''If the debug print scrolls continuously, the cause is definitely unstable LVDS signals''', resulting in changes to the 5 parameters shown above:
-(1)Ensure LVDS differential pairs use twisted pairs and are free from interference.
+(1) Ensure LVDS differential pairs use twisted pairs and are free from interference.
-(2)If InputPclk fluctuates, check if SSC (Spread Spectrum Clocking) is enabled; disable it for testing if possible.
+(2) If InputPclk fluctuates, check if SSC (Spread Spectrum Clocking) is enabled; disable it for testing if possible.
-(3)If HTotal or VTotal fluctuates, check the synchronization mode in software settings (usually Freerun or FrameLock). For LVDS-to-HDMI output, the mode must be Freerun with fixed HTotal/VTotal. For direct LVDS display, HTotal/VTotal may vary within a limited range without affecting the image. Thus, LVDS working for direct display does not guarantee valid LVDS-to-HDMI output.
+(3) If HTotal or VTotal fluctuates, check the synchronization mode in software settings (usually Freerun or FrameLock). For LVDS-to-HDMI output, the mode must be Freerun with fixed HTotal/VTotal. For direct LVDS display, HTotal/VTotal may vary within a limited range without affecting the image. Thus, LVDS working for direct display does not guarantee valid LVDS-to-HDMI output.