7" display options

3

32bits

Member
I am starting a new project and plan to use a Teensy 4.1 connected to a 7" display. Some years ago, for a previous project, I used a RA8875 with a Teensy 3.5 via SPI and this worked well, it only used the default font and some basic font resizing. So I an wondering if the RA8875 display still the best display option or have other display drivers been written to cater for more recent, larger displays? One requirement for the new project is multiple fonts / sizes and poss. using Adafruit GFX fonts, does the RA8875 or other display liburaries have provision for different fonts?

Thanks

Michael
 
There has been alot of work done in the recent weeks by a few forum memeber on severl displays:
ILI9488, NT35510, RA8875/6 to support faster communication protocols such as i8080 over 8 and 16 bit wide parallel busses.
All there librarys support custom fonts, drawing APIs etc

 
Thanks Rezo, I will check out your links. Do any of the displays have SPI support? as this might be fast enough for the screen updating.
 
As for 7" displays that support SPI.
If you look up at BuyDisplay for 7" supporting SPI, they have a few

RA8876 - We do have library @wwatson has a few versions of libraries.
RA8875 - We have the RA8875 library, installed by TeensyDuino. I believe that @mjs513 has the most up to date version of this.
LT7683 - Not sure, I believe this one is compatible with RA8876, but...

There are probably others. You might look at the recent thread asking about 10" displays
 
32bits said:
I am starting a new project and plan to use a Teensy 4.1 connected to a 7" display. Some years ago, for a previous project, I used a RA8875 with a Teensy 3.5 via SPI and this worked well, it only used the default font and some basic font resizing. So I an wondering if the RA8875 display still the best display option or have other display drivers been written to cater for more recent, larger displays? One requirement for the new project is multiple fonts / sizes and poss. using Adafruit GFX fonts, does the RA8875 or other display liburaries have provision for different fonts?

Thanks

Michael
Click to expand...
Hiya, as an alternative: out of curiosity, I recently got a 7in crowpanel HMI touchscreen display, which is controlled by built-in esp32 chip that can be programmed with the arduino IDE. Just playing with it atm, but essentially I want to eventually use it as an additional screen for the teensy 4.1. Loaded some test code into the display fairly easily, and can send info to control the HMI display over tx/rx pins. Heres a pic of it just wired rx/tx pins to a teensy 4.1, which also has an ILI9341 display. Have to unplug the tx/rx when uploading code to the HMI, though. Might be an alternative - loading alternative fonts on the HMI is straightforwards enough - on the test display I used a converted garamond font, as is loading bitmaps from the built-in SD card. Sprite functions make the screen pretty responsive. Offloading some of the graphics functions externally will hopefully save me some chunks of code and headaches :) Pretty cheap for what they are, bought mine on aliexpress. Seem to be numerous varieties of it, I got the elecrow crowpanel as it seemed to have better support and some online tutorials. Tutorials are mainly based around a HMI builder called squareline studio, but I'm just using the arduino libraries, and I just 3d printed (roughly) a bezel for mounting.
 

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Paul Hesketh said:
Hiya, as an alternative: out of curiosity, I recently got a 7in crowpanel HMI touchscreen display, which is controlled by built-in esp32 chip that can be programmed with the arduino IDE. Just playing with it atm, but essentially I want to eventually use it as an additional screen for the teensy 4.1. Loaded some test code into the display fairly easily, and can send info to control the HMI display over tx/rx pins. Heres a pic of it just wired rx/tx pins to a teensy 4.1, which also has an ILI9341 display. Have to unplug the tx/rx when uploading code to the HMI, though. Might be an alternative - loading alternative fonts on the HMI is straightforwards enough - on the test display I used a converted garamond font, as is loading bitmaps from the built-in SD card. Sprite functions make the screen pretty responsive. Offloading some of the graphics functions externally will hopefully save me some chunks of code and headaches :) Pretty cheap for what they are, bought mine on aliexpress. Seem to be numerous varieties of it, I got the elecrow crowpanel as it seemed to have better support and some online tutorials. Tutorials are mainly based around a HMI builder called squareline studio, but I'm just using the arduino libraries, and I just 3d printed (roughly) a bezel for mounting.
Click to expand...
It could end up similar to the Nextion displays (which I use).
 
Paul Hesketh said:
Hiya, as an alternative: out of curiosity, I recently got a 7in crowpanel HMI touchscreen display, which is controlled by built-in esp32 chip that can be programmed with the arduino IDE. Just playing with it atm, but essentially I want to eventually use it as an additional screen for the teensy 4.1. Loaded some test code into the display fairly easily, and can send info to control the HMI display over tx/rx pins. Heres a pic of it just wired rx/tx pins to a teensy 4.1, which also has an ILI9341 display. Have to unplug the tx/rx when uploading code to the HMI, though. Might be an alternative - loading alternative fonts on the HMI is straightforwards enough - on the test display I used a converted garamond font, as is loading bitmaps from the built-in SD card. Sprite functions make the screen pretty responsive. Offloading some of the graphics functions externally will hopefully save me some chunks of code and headaches :) Pretty cheap for what they are, bought mine on aliexpress. Seem to be numerous varieties of it, I got the elecrow crowpanel as it seemed to have better support and some online tutorials. Tutorials are mainly based around a HMI builder called squareline studio, but I'm just using the arduino libraries, and I just 3d printed (roughly) a bezel for mounting.
Click to expand...

Thanks Paul, how do you find the Crowpanel screen for contrast, brightness and veiwing angals, are they OK? I have seen a review which mentions the viewing angle is very restrictive and would be good to have your feedback.
 
32bits said:
Thanks Paul, how do you find the Crowpanel screen for contrast, brightness and veiwing angals, are they OK? I have seen a review which mentions the viewing angle is very restrictive and would be good to have your feedback.
Click to expand...
Yeah, viewing angle is certainly a little restricted, but as I'm just mounting flush in a 3U rack it's not much of an issue for me, and its no worse than a lot of other screens. Contrast and brightness seem fine, obviously dulled down in bright light/sunlight, but what I have noticed is that its pretty sensitive to fluctuations in power supply, giving scan lines on the screen, and I had to reduce the cfg.freq_write in the conf file down to 14000000 to stop the screen from flickering and wobbling. The lovyangfx library does have a function for setting display brightness, between 0 and 255, it could be that's been overlooked by some. Have managed to convert some fonts by using processing 4.3 and then an online file to hex converter, at tomeko.net. The crowpanel display seems to work ok with the arduino MIDI library, so atm I'm playing with sending it MIDI CC from the teensy over UART, which so far appears to work very nicely. If only they made a bezel that would mount in a eurocard rack, as 7in otherwise fits perfectly :). For me, a downside is that the pins for connectors are on the outside edges, rather than facing out from the back, so its a bit of a squeeze. Almost no pins for IO - got the UART, and I2C, but as that's shared with the touchscreen, I haven't used that at all. Serial MIDI is what I want it for, anyways, and reckon it's gonna be fine for that, as essentially, it's gonna be an external monitor for the teensy. I'll post a bit more when I've played with it a bit, as I've not had it long, and whilst it's not strictly teensy related as such, interfacing to a teensy might be of interest.

P.
 
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