SPI LCD with no chip select, thoughts on connecting it?

Other Hardware Displays
1

All,

I just received this SPI display 2.4 inch but is has no chip select. Anyone have an idea how to connect it?

https://www.amazon.com/gp/product/B0...?ie=UTF8&psc=1

Thanks in advance.

Kris

2-4inch.jpg
2-4inch.jpg3244×1492 232 KB

2

Your link does not work.

I guess that BLK means Backlight but BKL or BL would seem more intuitive.

Many controllers can work with a single bidirectional SDA line (no MISO) and / or 9-bit SPI (no DC).
But I would always expect a CS pin.

Does your display have an SD card?

David.

3

Thanks for getting back David.

This link should work

https://www.amazon.com/dp/B01J72L6C2/ref=cfb_at_prodpg

This display has no sd card and no touch. The only calls I see to create the display object both refer to a chip select. By project has a separate SD card with a chip select. I don't know, i've since emailed the chinese source--maybe i'll hear back

// Use hardware SPI (on Uno, #13, #12, #11) and the above for CS/DC
Adafruit_ILI9341 tft = Adafruit_ILI9341(TFT_CS, TFT_DC);
// If using the breakout, change pins as desired
//Adafruit_ILI9341 tft = Adafruit_ILI9341(TFT_CS, TFT_DC, TFT_MOSI, TFT_CLK, TFT_RST, TFT_MISO);

4

The ILI9341 is surprisingly relaxed about the /CS signal.

The first step is to identify "BLK" pin.

I would just read the display ID and check whether it works ok.
RES should be pulled high. e.g. with 10k

The controller is 3.3V. It looks as if the SMD resistors are in series. i.e. to limit death from 5V logic.
Diagnose out the schematic.

The popular Red 2.2" displays seem to have run out.
Replaced by Red 2.4" with or without a XPT2046 Touch chip mounted.

David.

5

Display powers up (all white is displayed). From what little the mfg says, BLK is pulled high and if I ground BLK the display goes black.

I've tried every pin combo I can think of. I've since contacted the mfg who claims to have some sample Arduino code--we'll see. i'll post what I find.

6

From memory, the Adafruit example reads a few registers and displays on the Serial Terminal.

I suggest that you connect all the named pins. Most importantly, the RES pin. And use a full constructor.

Adafruit examples omit the RES argument but it is available in all constructors.

David.

7

@Kris

Kris did you succeed to get the 2.4 TFT display working ?
i'm also struggling to get it connected without the CS pin

Cor

8

First off:

  1. do you have the same display as in #2 link ?
  2. when did you buy it ?
  3. do you have a link to the shop ?

Yes, you can run ILI9341 without CS i.e. hard-wired low.
Yes, it will work in SPI_MODE0 and SPI_MODE3

Yes, you can read registers.
No, you can NOT read the GRAM memory. (because there is no way to tell it to stop)

You should find all respectable libraries will work. Just don't attempt to read GRAM.

David.