B4R Question ST7735R TFT LCD with SDCard Reader: I'm having problems using both at the same time!

[Cableguy]

Hi guys,

I have this TFT with built in SDcard reader...
My issue is, I can use the display, even if the SDcard wiring is done (tested in software spi mode) but I can only use the sdcard reader if the display is not wired...
I guess this may be a CS pins thing but I can't make it out!
Please advise!

 

[Erel]

Try this Arduino example: https://github.com/adafruit/Adafrui...master/examples/spitftbitmap/spitftbitmap.ino

Does it work?

 

[Cableguy]

I have tried that. I can't really tell if it an hardware issue or wiring, the only thing I know is that even wiring only the sdcard, it only works correctly 90% of the times.
I am looking at different alternatives, similar to what I've done with the b4x logo

 

[Erel]

I have tried that.

Did it work?

 

[Cableguy]

No, as I said I can't get both LCD and SD card to work at the same time, and even the SD alone only seems to work 4/5 times.
My display is a cheap clone, so I reckon it's within the pricetag.

 

[Michael1968]

Hi Cableguy,

two years ago i worked with the ST7735R TFT.

i have two ,one from adafruite and one from sainsmart.

I had have some Problems with the TFT too. if i remember ,it was a Problem with a different SPI bus rate.

If i can find the Code....(on the old Computer) i will send it to you

best regards Michael

 

[Cableguy]

yes I read something about that, but even using software SPI emulation (initializeSoftwareSPI) it fails...
maybe it would work with a Mega since it has multiple SPI ports (?)

 

[mtd]

yes I read something about that, but even using software SPI emulation (initializeSoftwareSPI) it fails...
maybe it would work with a Mega since it has multiple SPI ports (?)

hello @Cableguy;
I new start a school project. and I need cheap touchpad+TFT screen for with use wemos board. What is your advice?
Not: can you share your screen connections code & diagrams

 

[Cableguy]

If you need the touch screen functionality then I would go with something like the nextion displays. The biggest advantage of them is that you only need 2 wires to the semis, the disadvantages are, it uses its own software to create the gui and uses an extra SD card to save/load the GUI.

 

[mtd]

If you need the touch screen functionality then I would go with something like the nextion displays. The biggest advantage of them is that you only need 2 wires to the semis, the disadvantages are, it uses its own software to create the gui and uses an extra SD card to save/load the GUI.

If I don't get it wrong;
I have to install an SD card for when I draw graphics on the screen. I can't write directly to the screen. is it CORRECT???

I cant see any Dc card sample videos.

 

[Cableguy]

Nextion displays are almost a "stand alone" solution, and communication is done by serial comm.
The GUI is created in a pc using the Nextion Software, and all events are treated internally by the LCD and passed by ID and value to the host board, in your case, the wemos.
Search YouTube for the keywords "Nextion" and you will see a bunch of tutorial available

 

[moty22]

No, as I said I can't get both LCD and SD card to work at the same time, and even the SD alone only seems to work 4/5 times.
My display is a cheap clone, so I reckon it's within the pricetag.

I know it's 2 years old post but maybe you still fighting the problem.
3 inputs to the SD cards have 10K resistors in series to the inputs, this value is too high (wrong design) and the input capacitance distort the rise time. if your drive signals are 3.3V then you can link the resistors. If your signals are 5V then you can solder 2K2 in parallel or in place, this was what I did to be able to use the SD.