Hi
I have a problem, the display won't show me anything. After connecting the power, the backlight seemed to blink. It is correctly detected by Read_User_Setup from the TFT_eSPI library. Powered from 3.3V. I corrected the User_Setup.h file.
What could have gone wrong?
ESP32 Wroom2 32 and programs via arduinoIDE as NodeMCU-32s
Since I cannot see that far it would be best if you posted a schematic, not a frizzy thing showing all connections, including power and ground. Also posting the code will give us an idea of what you are trying to accomplish.
A pencil drawn schematic is fine.
A Fritzing diagram is just fine. It even shows each wire colour.
Either schematic or Fritzing enables readers to check your wiring photo.
I don't know what gilshultz has against a frizzy thing. Fritzing diagrams show physical wiring, colours, ... very well.
David.
I don't know what gilshultz has against a frizzy thing. Fritzing diagrams show physical wiring, colours, ... very well.
Thank you David, for this response to a repeated remark that tends to annoy me whenever I encounter it.
Fritzing diagrams can be useful if they represent an actual wiring. But of course you are never sure.
Fritzing diagrams are recommended by books about Arduino in the German market. Maybe this is the cause for some cultural differences in opinion. I have no experience with it, as documentation is not my strength.
But any tool that helps documenting should be welcome.
Jean-Marc
That's the problem with Fritzing that users post - it just shows how things are wired. Most ICs are just represented as block boxes, you have to look them up to see what the various pins do. Even a simple transistor - which pin is base, collector, emitter? You can't tell. If users posted their schematic, and not a picture of how they wired it up, it makes offering help easier. We don't really care what color wires are used.
A schematic is more like a block diagram, you can see what each pin is, so it's more straightforward to look and say "Hey, you have the emitter and collector swapped", or "Hey, you have the shift register clock and the output register clock pins swapped" as examples.
Once the schematic is correct, then reviewing the breadboard layout and connections can be improved. "You don't have the connections in the same row" or "You have too many connections in that row".
@Jean-Marc,
I agree with you. Fritzing diagrams are excellent. However you do need accuracy e.g. correct resistor values, correct wire colours, ...
A text explanation is fine. e.g. different wire colour, ...
It is very frustrating for a newcomer to find that her new display does not work.
It requires a bit of effort to provide:
- post a link to your actual display e.g. Ebay sale page
- copy-paste or attach the TFT_eSPI User_Setup file
- post a photo of your actual wiring.
- post wiring colours. e.g. VCC = red, GND = black, TFT_DC = yellow, ...
But it makes it 10x more likely that a reader will be able to offer a solution.
And the OP has achieved success within minutes, hours, ...
All the same, we get lots of questions without a link to the display or a "readable" photo of the wiring.
TFT_eSPI just needs User_Setup file.
Other libraries need you to copy-paste the constructor statement and the Arduino board model
Most ICs are just represented as block boxes, you have to look them up to see what the various pins do. Even a simple transistor - which pin is base, collector, emitter? You can't tell. If users posted their schematic, and not a picture of how they wired it up, it makes offering help easier. We don't really care what color wires are used.
Most display wiring involves connecting a row of printed display module pins to an Arduino board.
A coloured wire is much easier to follow in a photo. e.g. TFT_DC = digital#9 - yellow.
You check both ends for colour. If multiple yellow wires, follow the wire.
Following a Fritzing is less prone to wiring errors than following a schematic.
For success you need correct constructor and arguments as well as matching wiring.
(Bodmer's libraries have a User_Setup file instead of constructor arguments)
Yes, for complex electronics the schematic is more important.
Which is why I always ask for a link to the display. (so that I can identify from the pcb layout)
This thread is about a 3.3V ESP32. So the display pcb is less critical.
But many threads are about a 5V Uno, Nano, ... In which case it is essential that level-shifters are used.
David.
thank you for your input. I appreciate your view for and your experience with complex electronics.
I would like to take profit of your experience and ask for a recommendation of a (free?) tool to draw schematics.
I don't like my hand drawing, and would never publish a picture of. But from time to time I would like to draw some schematics, before wiring e.g. a proto-board.
For simple connections of a display to a processors board pins a textual description often is best.
A Fritzing diagram is an easy to read representation, and a good picture with colored wires is a proof.
Jean-Marc
Fritzing does actual schematics, we very very occasionally see one posted here.
For projects that are not being turned into a PCB, ExpressSCH works well, and it is easy to create your own symbol if needed.
Here's an example.
@ewemarkum
There are quite a few things that can go wrong. The Read_User_Setup sketch only reports the settings picked up by the compiler, not that it is connected correctly.
Details needed to help are:
A picture helps as sometimes folk get the wiring wrong, even though it has been checked a hundred times, or use long wires that affect signal integrity, using pins for output that can actually only be used for input, or even forget to connect power/GND up. The list goes on...
A copy of your setup file and Read_User_Setup output (as a zip file) will help to confirm the compiler is picking up all the right settings.
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