ER-TFTM035-6 and Adafruit Feather

Other Hardware Displays
1

I would like to connect a ER-TFTM035-6 3.5" 480x320 TFT display board to an Adafruit Arduino Huzzah32 esp32 based board.

I connected the power, ground and backlight control to 3.3v and Gnd on the Huzzah32. I connected the CS and DC to those pins and the SPI pins.

The only library I could find that seemed to have ILI9488 support is the TFT_eSPI library, so I installed that.

I opened the UTFT_Demo_480x320.ino example. I set all the pins in the User_Setup.h file according to the pins I wired up.

When I power the Huzzah32 the screen lights up so I have the backlight working right.

As the sketch runs the screen is white and then flashes sort of black / gray from for several seconds. Then it just stays white for a few seconds. Then flashes some more.

Anyone have any experience with this configuration or something close? What might I be doing wrong?

I am hoping it is just some define I didn't set that needs to be.

2

These are the settings you need:

#define ILI9488_DRIVER     // WARNING: Do not connect ILI9488 display SDO to MISO if other devices share the SPI bus (TFT SDO does NOT tristate when CS is high)

#define TFT_MISO 19  // Do not connect to display SDO pin if other devices occupy SPI bus.
#define TFT_MOSI 23
#define TFT_SCLK 18
#define TFT_CS   15  // Chip select control pin
#define TFT_DC    2  // Data Command control pin
#define TFT_RST   4  // Reset pin (could connect to RST pin)

#define LOAD_GLCD   // Font 1. Original Adafruit 8 pixel font needs ~1820 bytes in FLASH
#define LOAD_FONT2  // Font 2. Small 16 pixel high font, needs ~3534 bytes in FLASH, 96 characters
#define LOAD_FONT4  // Font 4. Medium 26 pixel high font, needs ~5848 bytes in FLASH, 96 characters
#define LOAD_FONT6  // Font 6. Large 48 pixel font, needs ~2666 bytes in FLASH, only characters 1234567890:-.apm
#define LOAD_FONT7  // Font 7. 7 segment 48 pixel font, needs ~2438 bytes in FLASH, only characters 1234567890:-.
#define LOAD_FONT8  // Font 8. Large 75 pixel font needs ~3256 bytes in FLASH, only characters 1234567890:-.
#define LOAD_GFXFF  // FreeFonts. Include access to the 48 Adafruit_GFX free fonts FF1 to FF48 and custom fonts

#define SMOOTH_FONT

#define SPI_FREQUENCY  27000000
// #define SPI_FREQUENCY  40000000
// #define SPI_FREQUENCY  80000000

#define SPI_READ_FREQUENCY  20000000

The display is available with a number of interface options. Only a display configured for "4 wire SPI" will work with the library.

3

I see the Huzzah does not breakout many pins so try these:

#define TFT_MISO 19  // Do not connect to display SDO pin if other devices occupy SPI bus.
#define TFT_MOSI 18
#define TFT_SCLK  5
#define TFT_CS    4  // Chip select control pin
#define TFT_DC   12  // Data Command control pin
#define TFT_RST  13

Note that some ESP32 pins are input only, hence the choice above.

4

For some reason the forum didn't turn on emails notifications for me. I just saw this.

The display is configured for 4 wire spi.

These are the pins I used and wired it this way:

#define TFT_MISO 19
#define TFT_MOSI 18
#define TFT_SCLK 5
#define TFT_CS 15 // Chip select control pin
#define TFT_DC 32 // Data Command control pin

Should that work or do I need to specifically use the ones you mentioned?

5

Yes, that should work however I recommend that you define TFT_RST as a GPIO line and connect it to the TFT.

6

I think I just wired the RST line on the TFT to vss or vpp depending on what the data sheet said would allow it to run.

I will try connecting it to an actual pin and see if that makes a difference.

Thank you!

7

I have connected the RST line now and still get the same thing. Any more suggestions? I am using this setup and have double checked the pin connections multiple times:

The weird thing now is that I have RST line connected it only blinks a few times right after boot and then doesn't anymore. What controls the RST hi / low? The datasheet I have says it is active low.

Either way I am just getting this weird blinking of the screen. Any other ideas?

#define ILI9488_DRIVER // WARNING: Do not connect ILI9488 display SDO to MISO if other devices share the SPI bus (TFT SDO does NOT tristate when CS is high)

#define TFT_MISO 19
#define TFT_MOSI 18
#define TFT_SCLK 5
#define TFT_CS 15 // Chip select control pin
#define TFT_DC 32 // Data Command control pin
#define TFT_RST 4 // Reset pin (could connect to RST pin)

#define LOAD_GLCD // Font 1. Original Adafruit 8 pixel font needs ~1820 bytes in FLASH
#define LOAD_FONT2 // Font 2. Small 16 pixel high font, needs ~3534 bytes in FLASH, 96 characters
#define LOAD_FONT4 // Font 4. Medium 26 pixel high font, needs ~5848 bytes in FLASH, 96 characters
#define LOAD_FONT6 // Font 6. Large 48 pixel font, needs ~2666 bytes in FLASH, only characters 1234567890:-.apm
#define LOAD_FONT7 // Font 7. 7 segment 48 pixel font, needs ~2438 bytes in FLASH, only characters 1234567890:-.
#define LOAD_FONT8 // Font 8. Large 75 pixel font needs ~3256 bytes in FLASH, only characters 1234567890:-.
//#define LOAD_FONT8N // Font 8. Alternative to Font 8 above, slightly narrower, so 3 digits fit a 160 pixel TFT
#define LOAD_GFXFF // FreeFonts. Include access to the 48 Adafruit_GFX free fonts FF1 to FF48 and custom fonts

// Comment out the #define below to stop the SPIFFS filing system and smooth font code being loaded
// this will save ~20kbytes of FLASH
#define SMOOTH_FONT

#define SPI_FREQUENCY 27000000 // Actually sets it to 26.67MHz = 80/3
// #define SPI_FREQUENCY 40000000
// #define SPI_FREQUENCY 80000000

// Optional reduced SPI frequency for reading TFT
#define SPI_READ_FREQUENCY 20000000

// The XPT2046 requires a lower SPI clock rate of 2.5MHz so we define that here:
#define SPI_TOUCH_FREQUENCY 2500000

8

Arg, I feel really stupid. Turns out I was not putting the data / command pin to the right value in the header. As you can see in my post above it is 32, when I really have it solder to 33. I wanted it to be 33 because that is what the examples for Adafruit show. I don't know where I got 32. It might have been a default value somewhere and my old eyes didn't see the diff.

Now the example works and the display is working great.

Sorry for the trouble. Good learning lesson. Sometimes you can go over something a million times and if values are really close you still don't catch it.

9

No problem, glad to hear it is working now.

10

Would you mind if I asked a TFT_eSPI question here? I am just wondering if your library does BLIT operations to speed things up and if you do does it work with the ILI9488.

I have been using the Adafruit GFX library with an ILI9143 and before it didn't have BLIT, but now it does. The speed up is pretty dramatic.

11

Yes, TFT_eSPI implements efficient bit block copying of memory to the screen. This can be achieved via the Sprite class, see examples. TFT_eSPI supports 1,4,8 and 16 bit memory images via the pushImage function.

On STM32 processors the image block copy can be achieved via DMA but the performance improvement from DMA is generally small due the the efficiency of the block transfer approach used.

12

Thank you.

13

Same project running into a new related issue.

When I turn on SD card usage suddenly the TFT stops working. The SD card doesn't initialize either.

Any thoughts?

14

I presume you are using TFT_eSPI library. Turn on SPI transactions in the config.

15

When using an ESP32 the transaction support is automatically enabled because it is required to handle the dual processor mutex flags.

What connections are you using from the SD card and TFT to the ESP32?

I recommend you initialize the SD library first in setup() (i.e. before tft.begin();), this is because the TFT_eSPI constructor sets the TFT chip select high so the TFT does not then interfere with the SD initialization.

16

On the TFT break out board I have the SD and TFT SPI lines (miso, mosi, sck) connect together and then I have them going to the adafruit feather same lines as labeled. I then have a CS for the TFT and another for the SD on normal pins.

I will try what you said about trying to init the SD first. That is a good thing to try.

I did try removing the TFT CS line completely just to see if that would help, but it didn't.

17

Read this line.

18

Not sure how to separate the SDO. I am using the same SPI for both the TFT and SD. Don't know how to connect a different one and use it.

19

I was able to figure it out. I wasn't thinking through it properly. I just had to connect the SDO from the SD card and not the TFT to the esp32 MISO.

Now the TFT and the SD seem to work at the same time.

Now if I can just figure out what kind of touch controller this has on it. I know it is the cap touch version, but I can't find any data on how it works. The datasheet doesn't say anything other than the pins being i2c.

Does anyone know what cap touch controller this is?

20

Surely you read the description before you buy the screen.
BuyDisplay are pretty good when it comes to documentation, honesty, accuracy, ...

It is always wise to post a link to the actual item that you have bought. e.g. Ebay sale page, ...

I can only guess this screen with

capacitive touch panel with controller FT6236

They provide a FT6236 datasheet.

First hit for "Arduino FT6236 library" is Adafruit_FT6206_Library

If you have difficulty in discovering these things yourself, you should buy ready-made Arduino boards with ready-made Arduino Shields.

David.