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  • daBONDi
    replied


    Thx for the Fast Replay

    For my first prototype i got an uOLED 160G1 Rev 1C with PMMC 22, and it works perfectly with my current electronic.

    So i buyed 3 more and got uOLED 160G1 Rev 1G and there i have follow Problem:

    2 of them with the USB MB5 are power up correctly can load my SW and flash it with current PMMC 22

    With 1 of them it Power up (see the default SGG loading Screen, "4d Systems...") and on flash to PMMC 22 i got a wrong Errorcode -3 or some strange characters in a Message Box.

    Second problem with my current HW(Not MB5, serial connected with an MAX232 in between and powered), NON of the Rev 1G get powered on with same software and PMMC 22 , Rev 1C Display work correctly.

    What are the Changes between 1C and 1G did it use now more power?

    Thx in advice for the fast response.

    Leave a comment:


  • ESPsupport
    replied


    It's a bit hard to understand what behood was talking about. He seemed be saying that 22pF is greater than 0.1uF, but 0.1uf is 100,000 pF so what he said just doesn't make sense.

    Are you saying one of the displays powers up with an MB5, but not 'some other way'? What is that other way?

    The one you cannot load the PmmC in. What is displayed when you power it up with an MB5?

    Leave a comment:


  • daBONDi
    replied


    Got the Same problem
    uOLED 160G1 Rev 1C on my Prototype

    Now i buyed 3 More of the Displays and Got REV 1G

    Display dont Power UP :-( with USB MD5 it Power up.

    And on 1 of the 3 i cannot Load the GFX PMC R22 in.

    Where you but but the cap in? on the TX/RX line ? sorry im not an electronical expert.

    Leave a comment:


  • behood
    replied


    I totally forgot to respond to this thread... I've been playing with my screen that's now up and running and trying to move forward with my project.

    I did add a big cap. to my circuit, and all is well. The power dip during power up is much smaller and the screen starts up and is working as it should.

    For what it's worth, I was reading through the data sheet of the voltage regulator that is on the Parallax dev. board I was trying to use, and it looks like the output cap on the board isn't correct. The manufacturer calls for a minimum value of 22pF for the output cap, but only a 0.1 uF cap was installed. With the correct cap, the screen will turn on.

    Thanks for helping me resolve this...

    Brian

    Leave a comment:


  • ESPsupport
    replied


    I thought you were going to try a big bypass capacitor.

    Have you still got your old board? (What's the part number on the 5 legged chip just above the display socket, using the orientation you used on the Pic you posted on the 28/8. On that photo the chip has ~ 33BB written on it)

    The dip is almost certainly that chip 'cranking up'

    Leave a comment:


  • behood
    replied


    just tried a different uSD card without any luck... The problem persists. Any clue on the dip in the power line seen in the attached traces when the module is first powered up?

    Leave a comment:


  • behood
    replied


    I scoped the power line to my screen at work today and found something pretty darn interesting. I've attached the scope traces that show what is happening on the power line when the various power sources that I've been using power up.

    I know the above posts are super confusing; I was still figuring it out while we were conversing. I think this is the relevant information: My screen won't power on and display the splash screen if it's powered by either the circuitry I designed for this project or a dev. board made by Parallax. The output voltage of those two power sources is 4.94 and 4.96 v, respectively. However, if I power the screen from my bench supply at 4.96 V, it fires right up and I get the splash screen.

    As mentioned, I've attached the scope traces of the 5V rail during power up. For both of the power supplies that don't work, there is a big, momentary voltage drop about 14 mS in. The spike is there when the module is powered by the bench supply, but it's amplitude is smaller. I also have a trace of the power line when the module is powered by my dev. board and I toggle the reset line; the spike is there as well.

    I've also attached a photo that shows what I was scoping to be super clear about what I was doing.

    I looked in the Goldelox data sheet but I didn't see anything about brown-outs or what the processor does to deal with it. I also don't know why my RevG module worked. I know that the screen changed between the two revs. Does the new one require a higher voltage step-up or something? Do I just need a big fat bypass cap across the screen power lines?

    Thanks,
    Brian Attached files

    Leave a comment:


  • behood
    replied


    Sorry for the confusion. I'll try another uSD card, but this is the same card that was in the first module that I blew up. In fact, I got it from you guys when I bought the first module in 2008.

    Leave a comment:


  • behood
    replied


    Okay, so measuring the output of my USB port got me thinking... I built a LM317T based adj. voltage regulator into my power supply. I set the voltage to 4.94 and 4.96 volts and the screen worked both times. I set the voltage to 4.1 and, guess what, it powered on. I hate reverting to the supernatural for explanations, but I think my screen is possessed.

    The power supply on the original hardware is a switch-mode power supply that feeds an LM7805. That power supply should be a rock. The regulator on my dev. board is an LM2940. For giggles, I measured the current draw of the module with the splash screen displayed at .04A. So I'm not asking either regulator to do something it can't...

    I have no freaking clue... I swear I'm not yanking your chain

    I'll bring all of this crap into work and see if one of the EEs there has any idea what's going on. No one will believe me unless I show them.

    Thank you very much for the help, you've been great. I'll reply here if I find out anything worth while.

    Brian

    Leave a comment:


  • ESPsupport
    replied


    Sorry, I'm getting confused out of my little mind with all the changes.

    Could you perhaps try a different make of uSD card? (some of them are pretty finnicky power wise)

    Leave a comment:


  • behood
    replied


    Okay, so I may have to revise those data points above on account of me being dumb... I reverted back to the initialization code in the original post and plugged into my bench supply and it worked like it should. I got a 1-2 second delay and then the splash screen until I unplugged the module. My bench supply is putting out 5.15V. That's measured with an off-the-shelf DVOM, not my hack job. I don't know why it worked this time, but I'm not ruling out the possibility that I didn't turn the power supply on after I hooked it up during my previous attempt...

    That's good news, but I still have problems when I plug into the original hardware or my dev. board. Those output voltages are 4.94 and 4.96V, respectively. Pulling up the RX pin (pin 5) to 3.3V (pin 9) didn't solve the problem in either case, and yes, both power sources were on

    I just measured the output of my uUSB-CE5 to be 4.98V.

    I've attached a picture of the back of my module.

    Thanks,
    Brian Attached files

    Leave a comment:


  • ESPsupport
    replied


    That is so odd.

    Could you perhaps install a 10k resistor from RX to 3.3v, to see if that fixes it?

    Could you take a closeup photo of the display's circuit board?

    Leave a comment:


  • behood
    replied


    I have a few more data points:

    I just tried the same initialization code on a powered dev. board built by Parallax. I'm getting the same voltage reading and the same behavior. I'm pretty confident I can rule out the hardware of my project.

    Additionally, if I hook up only the power and ground pins on the module and leave the RX and TX pins unhooked, nothing happens. This is true with the the regulated power from my Parallax dev. board, when powered by own hardware, and when powered by a bench power supply. This is not correct behavior, right? It seems like when power is applied to the module, it should power up and start executing code regardless of if the com. lines are hooked up.

    Finally, the last data point is based on the following initialization code:

    func main()

    // Initialization Code
    /*
    media_Init(); // Initialize SD card
    gfx_Contrast(16); // Set contrast to full
    media_SetSector(0x0000, SPLASH); // Point to Spash Screen
    media_Image(0,0); // Show Splash Screen
    */

    com_AutoBaud(5000); // Set baud rate
    print("How about these apples");
    com_Init(com_Buff, 10, 0x00); // Initialize serial communication

    // Main Code -> Infinite Loop
    repeat
    // Poll the status of the comBuff & wait for a full packet from host
    while ( com_Full() == 0 )
    pause(1);
    wend

    ..........


    As before, when I plug the module into a power source without the comm. lines hooked up, nothing happens. The screen stays dark. If I plug the module into my uUSB-CE5, I get a 7 or 8 second pause before the screen displays the text. I suspect the pause is the time it takes for the screen to start up plus the 5 second auto-baud time-out time. When I do this, the text will be displayed until I unplug the module.

    Does the uUSB-CE5 do anything with the TX and RX lines when a module is plugged into it? I'm still a little learry about throwing 50 bucks at the problem to get another screen to test, but I think that's the only thing left...

    Thanks for helping me diagnose this.

    Brian

    Leave a comment:


  • behood
    replied


    Er, kind of I left my DVOM at work and all I have at home is a DIY voltmeter that I never finished calibrating... I know it reads a couple of tenths low, and it says the Rev1N screen input voltage is 4.6 v. The last stage in my power supply for this circuit is an LM7805, and their output voltages are darn close to nominal.

    I can't check the Rev1G module because I blew it up, which is how I came to own this shiny new Rev1N module... I was making a new power supply circuit for the system and forgot the bootstrap diode on the voltage regulator. The first time it worked great. The second time I turned it on, I sent 7-7.5 volts downstream of the regulator and took out almost every IC including the screen. Anyway, I can't check the old module

    Leave a comment:


  • ESPsupport
    replied


    Can you check the voltage available when using the new and the old modules?

    Leave a comment:

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