PTN3392BS,518 VGA output fails intermittently

[thkim]

I am using PTN3392BS,518 parts.

The VGA signal of PTN3392BS,518 part is not output intermittently.

It happens about once in 100 times.

I checked the HPD signal, and when the VGA signal is not output, I can see that the HPD PULSE signal is generated.

At this time, if the reset pin of PTN3392BS,518 is kept LOW for 3 seconds, the VGA signal is output normally.

It seems that the internal MCU has gone into a strange state.

I wonder if there is a workaround.

[TomasVaverka]

Hi,

What does it mean “It happens about once in 100 times.”? What is the test procedure? Or how to duplicate 1 time failure in 100 times test procedure?

You said “I can see that the HPD PULSE signal is generated”. If the PTN3392 detects DP link lost, then it will generate HPD pulse (on HPD pin) to the DP source (PC or GPU), and DP source should start new DP link training to establish DP link again.

“if the reset pin of PTN3392BS,518 is kept LOW for 3 seconds “ which will be resetting the PTN3392, and the PTN3392 will generate HPD pulse after internal resetting process is done.

Best regards,

Tomas

[thkim]

Thank you for your fast replying.

The test procedure checks the monitor screen by turning the AC power off and on and on repeatedly, and counts the number of fail.

When a problem occurs, if I force a push switch reset on the PTN3392, the broken DP link between the GPU and the PTN3392 seems to be reattached.

I wonder what kind of operation mechanism this is, is there any way to check if the PTN3392 is in DP link training state?

I wonder if there is a way to attach a DP Link without resetting the Push Switch.

[TomasVaverka]

Hi,

Please try to pull-up PNT3392 S0 pin (pin 33) to VDD through an 10K resistor, and test again to see whether issue can be resolved.

Best regards,

Tomas