That looks like the random startup state of the graphics RAM that is inside the display chip.
In setup() or somewhere else in your sketch, after tft.init(), you must clear the screen to the desired background colour, say with:
tft.fillScreen(TFT_BLACK);
bodmer:
@slessardOK, it looks like you have an ILI9163 based display then. The results indicate you have got the connections right.
You will need a resistor divider on the logic lines with that driver to avoid brightness modulation (happens when the display is being updated), I use 1k2 and 2k2 as I have lots of those values. Power the display from 5V, I notice that my display is fitted with a 3.0V regulator.
I intend to make a minor tweak to the library later today to add a "belt and braces" software reset at the start of initialisation.
Bodmer GOOD PLACE IS NECESSARY FOR THE DRIVER ST7735 RESISTENCIAS?
For 5V Arduino's a 1K2 series resistor can be used to interface with a ST7735 driver.
Example connections at the end of step 1 here.
bodmer;
My ST7735 TFT is working like a champ. You sir are a genius among geniuses.
Thanks for the feedback. Good luck with your project!
What's the reason this does not work on ESP8266-based MCUs? Regardless the speed, should I use the Adafruit ST7735 lib? Does it support I2C?
It is optimised for the AVR processors and uses machine coded sections to improve rendering speeds. This makes it 3 to 12 times faster depending on the graphics functions used.
If you wish to usse the display with an ESP8266 then you could try this library. It is optimised for the ESP8266.
This is the information dump
Looks like driver chip is: Unknown
`Hú5BþÿTFT driver register values:
===========================
Register 0x01: 0x00
Register 0x04: 0xE38835
Register 0x09: 0x610000
Register 0x0A: 0x08
Register 0x0B: 0x00
Register 0x0C: 0x06
Register 0x0D: 0x00
Register 0x0E: 0x00
Register 0x0F: 0x00
Register 0x2E: 0xFFFFFF
Register 0xDA: 0xE3
Register 0xDB: 0x88
Register 0xDC: 0x35
===========================
Looks like driver chip is: Unknown
Can help me identify
kacitran:
Can help me identify
I do not recognize the returned codes. Post pictures of your display, that may help (You seem to have copied my pictures from the original thread)!
You could just try different libraries and see which one works. The test results show you have got the connections working.
The display PCB is visually similar to mine but has a different TFT screen. I can only suggest you different graphics drivers to try to find one that works.
Hey Bodmer,
I tried this library on the boards I got from CN the other day. I get it almost to work with the 7735 library, The colors show up correctly, but a couple of inconsistencies exist when running the simple graphics test from your examples.
The first column and row of the display is not getting cleared or drawn.
There are some spurious horizontal lines in the multiple font test in the letter H of "Hello" .
There are some spurious horizontal lines in the testlines(ST7735_YELLOW), They are in different locations from the Hello test. One line at row 2, about 3/4 the lenght of the display, one about in the middle and about 5 short sections toward the bottom of the screen
I tried the Adafruit 7735 lib on the same device and it does not have the flaws mentioned above, but as you mentioned is a lot slower.
Any suggestions other than using the slow adafruit lib ?
Gary
Has anyone gotten to the point of putting side by side comparisons for using these chips - I have a driver (C not C#) for the S6D02a1 with fonts etc.... and I really don't want to re-invent the wheel to get the others running if someone has already done this...
Pete.
@scargill You can find the init code for the.two TFT drivers here:
https//github.com/Bodmer/TFT_eSPI/tree/master/TFT_Drivers
Well I have tried all 3 processor initialisations ( with S6D02A1 general routines) and though I can get text to appear for somewhat less than a second - result is always the same - in less than a second the display fades to white...
Well with a slight fix I now have one blog reader saying his works perfectly with the ST7735, I know my 6SD02A1 boards work a treat - but this one - is not having it - I can get the display up most of the time with text and graphics but within a fraction of a second it has faded to white... frustrating. The driver for the ILI9163 init doesn't do a thing... if anyone knows of ANOTHER chip these things could use - please do let me know.
The driver works great. However the black seems to be washed out. This is certainly an electrical issue. I put a 1.2k resistor to ground, and one between the nano and the display. When I disconnect the SDA line, the issue is fixed. Obviously this isn't a solution. All the color are washed out, and the black is pretty much gray. If I removed the sda line, the colors become crisp. When the sda line is reconnected it goes back to washed out. Have any of you seen this issue, and know of a fix?
It appears that the SDA line is supplying current to the display, check the inline resistor values are correct.
If that is OK, then check if the display is still grey after drawing a single black pixel with say a long delay afterwards. Writing black to the screen should set the SDA line low so it does not source power. Also try the same test when drawing a white pixel, this sets the SDA line high. The idea of this test is to see if current being supplied by the SDA line is really affecting the grey level.
Note, if colours are inverse then the SDA line may be low for white and high for black.
Thanks for your help, I had accidentally put the grounding resistor to the wrong pin. Once the 1.2k resistor was connected to the proper SDA pin, the colors became vibrant.
