Kippah with LCD Fades Out Moderators: adafruit_support_bill, adafruit

[Slowpokee]

I am interfacing a (Raspberry Pi 3B) with (5" 40-pin TFT Display - 800x480 with Touchscreen) using the Kippah interface with a ribbon cable. I followed the instructions with updating, upgrading, download and install libraries, and edit config.txt. the screen will 1st show an RGB box image then the Raspberry logo startup. Then it will slowly fade and go black. I shorted the extra 25ma = 50ma total as specified for 5" displays. Initially I thought it a hardware issue but this feels like a possible configuration. Also the test python program doesn't read or write to EEprom via GPIO. SPI and I2C are disabled in config.

[adafruit_support_mike]

The four-color image is a symptom of low power.

Check the voltages on the 5V and 3.3V pins to see if the system is browning out.

[Slowpokee]

Greetings Mike,
I read the voltage across pin 1 and 2. Pin 1 registered at 4.2~4.3 volts and pin 2 at 5.02 volts. This seems high to me. The total consuming current on the supply is around 1.2 then settles at .5 amps. I compared my raspberry pi 4 and it's power buss sits at 3.3 on pin 1. Do the version 3's typically go this high? Could this be causing an over voltage situation? It looks like a low voltage problem on the screen.

[Slowpokee]

The four-color image is a symptom of low power.

Check the voltages on the 5V and 3.3V pins to see if the system is browning out.

I ended up swapping my Pi 3 with a new Pi 4. The screen just goes white then to blank. This is also a new display that came in yesterday. I was able to test the screen using a different interface with HDMI inputs and it works so the screen is not an issue. To me the common denominator is the Kippach card!

[Slowpokee]

The four-color image is a symptom of low power.

Check the voltages on the 5V and 3.3V pins to see if the system is browning out.

Also my display is the one with the touch screen. The description on (https://learn.adafruit.com/adafruit-dpi ... stallation) mentions using a USB interface with the card in order to communicate with the touch screen. My Kippah is missing the USB chip and connector. However, I don't know if this would interfere with the display data as that is a separate item all together.

[adafruit_support_mike]

Pin 1 registered at 4.2~4.3 volts

That's higher than it should be, and could mean that the RasPi's 3.3V regulator is damaged.

My Kippah is missing the USB chip and connector. However, I don't know if this would interfere with the display data as that is a separate item all together.

The display and AR1100 USB touchscreen controller are independent circuits, yes. The one should have no effect on the other.

To me the common denominator is the Kippach card!

The Kippah firmware would be another common factor. The whole project is a fairly technical hack, and isn't guaranteed to work with versions of Raspbian other than the 2019/04/11 version of Raspbian. Are you sure you're using that OS image?

https://learn.adafruit.com/portable-kip ... stallation

[Slowpokee]

Since this board or firmware is not compatible with my RP4, can I return it and apply the credit to a RA8875 Driver Board?

[adafruit_support_mike]

When did you get the display, and is it still in the same condition as when it came out of the bag?

[Slowpokee]

The display is brand new (4 days old) as I ordered a 2nd one thinking that was the 1st issue. I am now using a new Raspberry 4 and LCD. This display card interface is the final link in the hardware chain! That's why I want to exchange it for the higher end SPI interface. You mentioned the current driver is old and kludgy.

[adafruit_support_mike]

You're well within our 30-day return/replace window, so if the display is still in original condition you can do an at-will return and we'll credit your account for its price. You'll have to pay the return shipping.

Send a note containing a link to this page and your order number to support@adafruit.com. The folks there will help you.

[Slowpokee]

Sure, please start the process so I can order an interface that works

[adafruit_support_mike]

I've done my part: this thread is your authorization.

The next step it for you to contact the folks on our business team at support@adafruit.com.