We are having problems passing EMC (EMV) because of ringing in LCD_VSYNC / HSYNC. We have changed the lcdbs registry setting according to your article here. It seems like VSYNC / HSYNC aren’t affected by adjusting lcdbs. Is that correct? Do you have suggestions for us?
Thanks so much!
Daniel
Dear @MessagePump
Changing the drive strength works as described in the developer page article.
I tested it on WEC7 V2.0:
-
Connected an oscilloscope to SODIMM
68 (LCD1_LCLK) -
Added the following registry value:
[HKLM\Software\Nvidia Corporation\NVDDI\LCD]
lcdbs = 0xf0000000 -
Saved the Registry
-
Rebooted the device
The measurements confirmed that the falling edge was much steeper during boot than later, after the lcdbs setting was applied. The same is true for the rising edge.
Default Drive Strength:
[upload|Jvq/2flMRhiCM6eCK7VelEbZXB0=]
Reduced Drive Strength:
[upload|dXjknB7CjZr0GLh/L+hVm6+ap5U=]|
The setting can be verified and changed on the fly using our Reg Access Tool:
The value stored in the lcdbs setting is copied to the physical address 0x7000089c.
To apply the same drive strength already in the boot phase, the same setting as for lcdbs can be done also in the bootloader config block, under ss.bsTeg.
Regards, Andy
Thanks so much for your thorough answer! Toradex support is really outstanding.