Hey all, I know I’m gonna get flamed over this but nothing ventured nothing gained….
I’m building a small display to show engine data on a 4x4 which I’m intending to interface to an Arduino mega, actually a Speeduino but with my own code, I’ve used a few 2.8 inch tft’s and many text only lcds but fancied something a bit bigger after all it’s a 4x4 that gets thrown around so need some large text! It also needs to be sunlight readable.
I have an Adafruit featherwing 3.5 tft that I was planning to match up with a Feather 328P, there are a couple of issues with this, such as the 328P when fitted to the rear of the tft makes for quite a chunky unit completely ruining the slim outline of the TFT and worst the 328P doesn’t work on Linux or from what I can see any other system so it got hurled over arm into the nearest bin, if nothing else just to stop me wasting time trying to make it work.
I have a 3.3V pro mini in the post which I think will fit snuggly behind the screen, then I can squeeze in either a can bus or a tiny RS232 breakout board to link up with the Mega. Sadly there are no pin markings on the rear of the display but I’ve got the schematics to hand.
I’ve done a bit of searching however the internet is somewhat blocked at work so before I dive into this too deep is this a feasible proposition? I believe the Feather 328P used the same processor as the pro mini so I’m guessing if I match up the appropriate SPI and such pins things should work? I do wonder if an 8Mhz chip might struggle with a fairly large screen, I am only planning to use a bit of text, a handful of floats and some simple bar graphs.
I do believe there may be timing issues between the tft and Arduino, I can’t find were I found this out so may not be true. I know the backlight will take a bit of juice so won’t try to run it from the mini, I think it’s actually 5V but dropped to 3.3V via a couple of diodes.
Sorry for the long post but wanted to add as much info as possible.
Why not use a Raspberry Pi if Linux is what you are after?
An Arduino can handle Linux, as this fellow demonstrated.
[Linux on an 8-bit micro? - Dmitry.GR](http://"http://"http://\"Dmitry.GR: Projects. Linux on 8bit""")
I think he used a '1284P to take advantage of the 16K SRAM it provides, vs just 8K on a Mega.
He overclocked it a bit 24 MHz vs spec max of 20 MHz.
By the time it is ready to go, you will likely be at your destination tho.
Thanks CrossRoads, unfortuneately that link is blocked by our server.
I did try a raspberry pi with a 7 in touch screen which when using pygame gives a fabulous unrivalled display and is a piece of cake to interface to an Arduino, I've got several running as weather stations however it's impossible to get a clean boot. The screen will initially show the square rainbow which wasn't a big issue but then would show a white screen for a couple of seconds which on a dark winters night was like looking into a nuclear blast :o
Oh and like you say it takes for ever to boot up.
Just managed to view that link on my unrestricted home machine...wow thats impressive, thats oldschool 
You've kind of got me thinking about the raspberry pi again but I've blown £40 on the featherwing display so want to get some sort of use out of it.
How about a matching Adafruit board to go with it?
" it works best with our faster boards like the ESP8266, ESP32, M4, M0, nRF52, WICED, and Teensy"
I was origionaly intending to use a feather 328P which uses the same chip as the pro mini but there was no way I could get it program with ubunto (linux) so I've lost faith in the feather range of boards which is a shame as I was looking forward to playing with a differnt platform.
Im not sure how well the 328P would have worked as it was only 8Mhz but would have been a good starting point.
Bit of an update,
I though I would pluck the feather out of the bin and give it one last chance on the works windows 10 machine and I managed to load the brink without delay routine, I know it still wont program on Linux so I cant program it at home but its a huge step forward
Edit. OK I've now got the Adafruit graphic example running on the screen and it is awesome!
Just need to find a way of programming it using Linux now:)
OK, I've been uploading sketches to the Feather / display all day using windows 10 but as soon as I try at home with Ubunto it just deosnt want to know, I'm getting the following error message;
Arduino: 1.8.10 (Linux), Board: "Arduino Pro or Pro Mini, ATmega328P (3.3V, 8 MHz)"
Sketch uses 19882 bytes (64%) of program storage space. Maximum is 30720 bytes.
Global variables use 717 bytes (35%) of dynamic memory, leaving 1331 bytes for local variables. Maximum is 2048 bytes.
avrdude: stk500_recv(): programmer is not responding
avrdude: stk500_recv(): programmer is not responding
avrdude: stk500_recv(): programmer is not responding
avrdude: initialization failed, rc=-1
Double check connections and try again, or use -F to override
this check.
avrdude: stk500_recv(): programmer is not responding
Problem uploading to board. See http://www.arduino.cc/en/Guide/Troubleshooting#upload for suggestions.
This report would have more information with
"Show verbose output during compilation"
option enabled in File -> Preferences.
I've just uploaded and installed the latest IDE (1.8.10).
The display resets when I try uploading ie the screen turns white and the display reloads the existing screen text ect.
I really don't know what else to do, any suggestions? this may be the wrong section for Feather boards. If I cant program this at home its unusable.