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Hi Martin!

Wow, and with humidity

I try to test with some of mine display too on your board, working perfect So Martin what is the next step, will you share your information and code with the
MM guy´s so we, you, they could create a st7789 component for Flowcode And what can I do to help?

Martin please send me in PM your adress and I will return your project incl. a couble of extra display or I will pay you for your for the part´s, you choose.?

Br Jorgen

Phew - it still works
I was beginning to think I'd dreamed it.... It would be very interesting to know if any of the other displays work or not - it could just be my soldering technique really sucks and the board is getting a bit 'warm'.

I'd really like to test it with the ATTiny85 and my SPI (1.67MHz) - as the board should cope okay. Just don't have one that works at present

I've not had time (work pressures) - but I'd like to implement scrolling.

The code is as posted (just added a humidity printout) - and there are one or two problems - so testing would be good. Try all the functions and find what works and what doesn't. If we can work out why some boards (and the MM component) don't work then it's cracked. Simulation would be good too - and I'd need a lot of help with that.

Martin

Martin have you seen this:

http://www.lcdwiki.com/Main_Page

Unfortunately, no st7789 among. But could maybe help another time.

Jorgen

thanks Jorgen. Looks like a good resource.

How goes the testing? Do all your displays work okay?

Martin

Yes all of them, I have 5pc. and will share with you. So Martin what do we next?

Jorgen

Perhaps you could send me a working display. I can make another driver board.

Not sure why none of my other boards work - perhaps a bad batch?

I'll PM my details..

Martin

Hi Martin!

Meanwhile (for fun) you wait for the st7789 parcel I created a little project with the more smaller display 0.96 ssd1331 display with a DHT22 sensor. (only temp).

And of course for all FC guy´s here

Unforunately I forgot to put one of these ssd 1331 display for you in the packet too, d.. it


The display work fine in the FC8/ component (will try the FC9 too). It would be nice if your st7789 component could be similar

Anyway, the st7789 display is a little bigger.

Br Jorgen

So many displays (or is it display drivers?)

Will have a look and see - what features would you like to see though

d.. it

- good advice for holes in the socks?

Martin

Progress - so far...

See https://youtu.be/1rtbY4XN9Tc

Martin

Hi Martin,

did you ever find a solution for the 'new' displays?

I happen to have a lot of them, too. I first ordered a lot (~50) of these displays for my students and just to be sure another similar batch later.
Every display from the first shipment works, and none from the second. So obviously there is a systematic bug somewhere in the production. It could be anything, but in the best case scenario it would be a new ST7789 version requiring a bit different initialization.

Yes, I think so.

There seem to be several variants which need slightly different startup sequences.

If you give me a pointer to the display you are using I'll see what I can do...

Once you have the initialisation correct the rest is fairly straightforward..

Martin

The displays were from Banggood "1.3 Inch IPS TFT LCD Display 240*240 Color HD LCD Screen 3.3V ST7789 Driver Module", bought 11/2021.

From your pictures and description, I guess they are the same modules you have.

It is a pity that a half of them do not (yet) work... the rest are very nice and fast. 62.5 MHz SPI without a problem (the fastest SPI I have ever witnessed).

Yes - I got a couple of batches at about that time and some worked and some not - hence the above thread...

As a test - try running them using the Adafruit libraries and the Arduino IDE - if they work it's an initialisation problem (and I'd guess you'd be very unlucky to get 50 duff displays...)

If I remember - there were several variants described as Red, Black and Green tab?

Martin

Found out the problem!

Had an older project with an AtMega4808 with a display and just to verify that the 'broken' displays do not work, tested one of them with it. It worked! After a couple of hours of comparing the codes (the current one is with Raspberry Pico), I found out that the SPI settings were not identical. While the datasheet of the ST7789 implies POL=0 PHA=0, the CS-less connection of these cheap displays seems to require POL=1 PHA=1. HOWEVER, half of the displays also work reliably with POL=1 PHA=0 (with Pico, at least). So, it was this that got me stuck - since some of the displays did work 100% reliably, it never occurred to me that the settings could be so wrong.

So,
1) My bad
2) There really are 2 versions around, since the behavior is 100% repeatable and consistent for each individual display
3) The ditching of CS is an idiotic place to save 1 pin worth of cost
4) A working system can easily be mistaken for a correct system