Official P2 display not working :(
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Posts: 193
in Propeller 2
I'm running the spiral-demo for my P2 eval board. On a DELL HDMI-capable monitor, it works just fine. But not on my 7" or what it is display 
It is supplied with 5V whit, GND black, and of course uses an HDMI cable. This cable works otherwise. I see the display put out a blue screen (I presume while booting/initializing), and then it turns black.
Any suggestions?
Comments
Yes, sounds like the monitor is powering up, but not "seeing" the video signal.
I can't remember the colors of the monitor cables, but anyway the PCB board is marked with the power information. Two wires are positive and two are GND... Actually.. was it 5V or 12V for that monitor.... hmm.. (I can go check these details if it would help - might take me an hour).
And also make sure the 5V jumper/short is applied on the HDMI breakout board, so the monitor knows to wake-up. Depending on which version of the HDMI add-on you have, there might be two holes marked for 5V which you can short out (or install a 2-pin header and use a shunt). OR... maybe a single 5V hole by the HDMI socket, which you run a jumper from to any 5V pin on the EVAL board.
These displays are just flaky IME. Wiggle the cables a bit. Also, you'll need a wire to short some of the button pads to enter the OSD, the factory settings are awful (and even them, there is no perfect setting)
Found this wiring helper... and yes, it is 5V
Another tidbit...
The monitor draws almost 500mA when running, and requires a little more to power-up. Having a 1Amp 5V supply for the monitor would be safe. (ie. For sure, sharing the USB supply from a PC won't be enough to power the monitor - unless perhaps you are using a decent powered hub with quality high-current rated cables)
If you see flickering, or failure to start, that usually indicates lack of power- it might be that the voltage source is too weak, or that the interconnecting cables have too high resistance. Either way, the voltage is dropping as the monitor tries to power on, causing the flicker loop.
Oh yea, they need decent juice, too. Normal USB power doesn't cut it and it will not start up properly.
Finally, here's a picture of the jumper with shunt installed, to allow on/off control of the 5V wake-up signal, required by some HDMI monitors.
Having pondered a little more, I'm not certain the LCD monitor requires the signal... but won't harm to add the jumper in-case it does. I suppose logically, as these might have been in-car monitors, then the enable or wake-up signal may well be useful.
ps. Glorious green color jumper not essential!
Powersupply it was! It was barely enough, I had my bench-supply (by chance) at ~440mA, and it draws 40mA more... !
Thanks for the support, folks!
All monitors I used don't need this 5V. However, all HDMI switches I used need it. Without this 5V the switch cannot recognize that the port is active. So I have my HDMI boards shunted.
And remark - 2 of 3 HDMI accessory boards I got didn't work because of excessive solder on HDMI socked (several pins shorted). That was one minute repair but first you have to know what is wrong.