Fast display ST7789!

[jgu1]

Hi MArtin!

I sense it is not straightforward to make a component for this display. For my sake, do not spend more energy and time working on it.

I thank you many times for your efforts. I appreciate your work and the time you have spent.

Br

Jorgen

[mnf]

disp.jpg (213.79 KiB) Viewed 63584 times

Almost done now....

Something odd that it's not starting reliably for you.. Seems rock solid on a Nano... I did a quick thermometer with a DHT22 - but missed on the 'degrees' symbol.

Martin

st7789.fcfx

(98.74 KiB) Downloaded 434 times

Just with temp added (DHT22 on d2) - still displays rainbow, lines and text before swapping to this display...

Martin

[mnf]

As a thought - the display seems'sensitive' to fluctuations in power - if I touch the 3.3v connector then it often make the display fail. Perhaps s capacitor and maybe a separate 3.3v supply (not sure how much per a Uno 3.3v pin can supply?)

Martin

[jgu1]

Wov, Martin.
Yes my experience with these display are also they are very sense concerning the power.

I Don`t know why But I see that in many other project some are connecting the datapin directly to the Arduino and other make an devider with resistor. I see that you use the drop Down conv. from 5V to 3V. I have tryed with all these, and the display is not working for me. I Saw in an another project that a guy only was using resistor in serie, the I try this, only use 2k7 ohm resistor in serie with the datapin, working, and of course the supply directly to 3.3v

So, in my project ( or educ8 tv ) i have only these resistor in serie, and it work, so I don`t understand how the voltage can change out of the Arduino because you are programming.

But you are rigth, something migth happend, because sometime I can see the abcdefgh, and other time the screen is Black.Strange Martin.

Br Jorgen

[mnf]

I've set up the thermometer (and added humidity) on a long term test for today...

Tonight I'll try with a 3v3 MCU...
Try adding a smoothing capacitor across VCC/GND?

I don't think a Nano is significantly different to a Uno - both should be able to supply 50ma on the 3.3v pin (and possibly up to 150ma)

Martin

[mnf]

A frustrating evening..

Nano ran happily all day (and display restarted after a power cut). Slightly worryingly - my bedroom hit a 'peak' of 12.6C. Toasty...

But my attempts to get a 3v3 Micro (Pro) running failed... Might be easiest to use an ATTiny85 running at 3.3v - but my USBTiny is v1 and 5v only - so programming would be awkward (and necessitate plugging/unplugging wire each time )

So - no progress at all today. I'd like to do a scroll (which would work well with the text routine?) but after that - not many ideas. I'll add a full 'copy bitmap' that works with full bitmap files - this would do away with the conversion needed currently - which just strips off the header and copies data to code that can be used (and makes using bitmap 'format' make sense). I think I'm too lazy to do orientation - just have to fix it in the box the other way around? Any volunteers to think on this? (Actually text and lines are fairly easy - plot can do all the work, but this will make everything slower.)

How have you got on? Any progress getting it to work ??

Martin

[jgu1]

Hi Martin

Glad your working well.
I hope you slept well despite the cold in your bedroom

No unfortunately no progress here. I have tried several times with the same configuration and pin connections. I have checked these several times. I have not been able to watch ABCDEFGH again. But I can see sometimes I upload it is like I still see some of the previous text from the test with the thermometer. from IDE. Could there be something with the initialization.
Here is another funny project with a clock and rtc. Arduino IDE, it works without problems every time. Hope you can find out something, would rather use FC8 and create my own project
Jorgen

[mnf]

See PM for suggestion...

[mnf]

And I think I've found the problem..

There seem to be'variants' of the display. I have two, which I will call the old displays - the screen print on the back is poor quality and some 'new' displays with much better printing.

The 'old' displays work perfectly, and the new ones not at all. I tried two of the newer displays too - and unless I messed up the soldering on both, thave something different about them... Neither of the new displays worked at all.

Will investigate more..

Martin

[jgu1]

Ok Martin.

Try to of course the supply directly to 3,3V and the datapin with a resistor 2k7 in serie to the datapin. This is what I have don

[mnf]

Today I'll try with resistors..
I can't get the new displays to display anything - I tried fast library, adafruit library too without success - maybe my soldering? Can you point me to the examples you are using.
Maybe some differences - there seem to be 3 versions in the datasheets..

Martin

[jgu1]

Hi Martin!

First when you test with the resistor in serie, use an unused display. My experience, first test with 5V without resistor display damaged.

Here you can find all the information of the clock:

https://github.com/cbm80amiga/ST7789_Watch_2bit
https://www.youtube.com/watch?v=jFGDFuL ... e=youtu.be
--------------------------------------------------------------------------------------
Temperature:
https://www.youtube.com/watch?v=-nECx4DOE84
https://educ8s.tv/arduino-st7789-tutorial/

Note that "Nicki" connect the datapin directly to display. Damaged my display, 2k2 resistor in serie, working

Hope it´s usefull.

Jorgen

[mnf]

I wired a working display with 2k2 resistors on all the data lines - signals looks ok on dc and SDA but clock doesn't work - I checked with oscilloscope.. either signal is too fast for a resistor reduction, it or the resistor is faulty (maybe my soldering?)

No joy - yet.. the 'newer' type displays I can't get to work at all!

Martin

[jgu1]

well ok Martin! Not good. Maybe we should drop these display?

[mnf]

Not yet - it's a very nice display.... Easy to work with too when it's working

I'll hopefully have a bit more time to play over the weekend - and I've just received a 3v3 usb-tiny (alike) from Bangood...

Martin

[jgu1]

ok Martin I agree, like it too. I have just received 5 new from Ebay I will test them.

[jgu1]

Just made a test with the new display, They work fine all of them with the Arduino Ide. (Clock and Ds18b20) and 2k7k

Send me your adress and I will ship one for you which I have seen working here, then you can test too, if ok. Maybe they are different.

Jorgen

[mnf]

Phew - not much progress. Messed up one display trying with resistors..

Just had a play with with an ATTiny85 (which should run at 3v3) - but although SCL seems good, there doesn't seem to be any signal on MOSI. So no joy. Anyone used SPI on the ATTiny85?

Took a long time to get a USBasp programmer working with FC - and then they don't seem to work when set at 3v3 output. (This seems to be a 'feature' of the programmer rather than FC)

Martin

[mnf]

Hi Jorgen,

Tried this evening to get this to work - and no joy. But I only have displays that don't seem to work at all (what I called 'new' type) (Posted a working version - should be with you soon?)

I've wired a display up to a ATTiny85 (which can work at 3.3v) - but after a little work with the hardware SPI not working (it doesn't work in FC9 either) had to create my own SPI routines (these have an advantage of being ~4 times faster - so hopefully display will be good it does work!)

So - I have another 'working' display - but I did a silly thing. I soldered it to a breadboard and there wasn't room for a level converter (don't ask) - and resistors didn't work (SCL). Sound of face hitting palm!
Tonight I'll try and 'unsolder' it - but this may or may not work out well....

Martin

[jgu1]

Hi Martin!

Ok, sound good, look forward to test.
Hopefully it in the end it will work and you/MM can create a component for this display like the other in FC. And yes, st7789 doesn´t work in FC9 either Ili9341
I would like to pay your shipping costs, tell me?
If you want, I would like to send you a few of the displays I have purchased and which I have tested on the Arduino IDE working. Free and for your trouble and struggle

Bougth them here : https://www.ebay.com/itm/5PCS-1-3-Inch- ... 2749.l2649

Br Jorgen

[mnf]

It's Christmas...

Surprised it hasn't reached you yet though... Santa stuck in customs.

It's very odd - I had two displays which worked beautifully and then 3 (another batch from Banggood) - which won't work at all. Still - not much time to work with them at present. Work is too busy So maybe when Christmas is past all will become easier. The world will slowly get back to normal in 2021 (we hope).

Martin

[kersing]

The eBay add uses strange names for the pins of the SPI interface. Sda and scl look more like i2c to me.

[mnf]

It's mostly SPI.. There's also a pin to switch between data and commands.

Martin

[jgu1]

Hi Martin!

Note in my mailbox from the postman. A parcel to me from Uk. Guess it´s from you. I pick it up tommorow. Look forward to test.

Thank´s in advance.

Br Jorgen

[mnf]

Crikes - that took a time...

If it survived the journey - just move the display from it's 'parking' place to correct place and add USB power... Has the last program 'installed'..

Martin