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Post by jamesbowman on Oct 24, 2017 11:50:09 GMT -8
Sounds like some electrical problem with the HotMCU power supply to the FT800.
Have you tried with an actual Gameduino?
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Post by ED on Oct 29, 2017 10:49:02 GMT -8
No I have not tried a Gameduino but I should I only stumbled on your Gameduino library after getting the HotMCU FT800. I certainly appreciate the time you have spent helping me and writing the library. If I discover anything further I will be sure and post it here. I have noticed that when the display locks up, the orange LED on the Teensy stays lit. Earlier in this discovery process I was associating this behavior with touch problems but it seems more likely now to point to communication issues. Interestingly if I unplug the display in this locked up state, the LED does not change, still stays on solid. Since this LED is also tied to the CLK line it's almost as if the Teensy clocks something out, waits for a response and then never gets it and just leaves the clock in the last state. again, thanks for your time and efforts, all the best, Eric
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Post by Donziboy2 on Dec 28, 2017 5:14:45 GMT -8
Hello All. Just started unboxing the 5" FT811's I bought this year and figured I would read up a little on them.
ED, if you look at the provided schematic for your screen it is configured for a 5V power input, the logic IC's for SPI are powered from 3.3V and will accept 3.3V or 5V signals. You can power the screen from the VIN pin of the Teensy 3.1, which is basically taking power from the USB. Or you can use an external supply. In general its best to avoid powering intensive items like screens directly from the Teensy.
An odd thing I see with the schematic is they use a 2R2 resistor to set the LED current. The RT9293B uses a 300mV feedback voltage so with a 2.2R resistor your looking at 136mA which seems really high. Before you panic it may be a typo thou, take a look at R1 and if you cant read the value measure it with a meter. It should be 22R not 2R2.
I have worked with a few screens with the Teensy and have found that the biggest issue is bad connections and long wires. SPI at high frequencies should not be run long distances.
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