Hi folks,
I use a TFP410 to convert 24bit RGB data (plus sync) to a DVI stream which is fed to a scaler and finally to a LCD panel.
It works quite ok, but on some boards I only get intermitting DVI signals. The CLK channel is running without pause, but the data channels send LVDS levels only for about 110ms and then pause for about 100ms. Of course no monitor or scaler works with such a stuttering timing.
Anybody any idea where that could result from?
Here the signals fed to the TFP410:
- 24 bit of RGB data, changing around the falling edge of the clock
- a 62MHz clock signal
- HSync, VSync and DE signals as needed
- ISEL = low (=no I²C)
- PD = high
- BSEL = high (=24 bit data, single edge)
- DSEL = low (=single edged CLK)
- EDGE = high (= latch on rising edge of CLK)
- SCAN _EN = low (= normal operation)
- EXT_RES: 510R to AVCC
- DKEN = low (= DK1..3 unused)
All signals are fed from/to the chip via 22R serial terminated PCB traces and the output of the TFP410 goes to a HDMI connector where either a monitor's DVI input or a termination network is attached.
Greetings from Germany,
Stefan
