3.5 tft lcd code mcufriend factory

I bought four MCU Friend 3.5″ TFT shields.  And, unfortunately, they have spiraled me into a deep, dark place trying to figure out how to use them.  The the documentation consists of a sticker on the antistatic bag, a picture of the shield with a list of 5 different possible LCD drivers, a pinout, and a block of code that supposedly represents the startup code.  The unfortunate part is that none of these have been exactly right – they all have errors.  This article is a description of the journey to figuring out how to use them.

Here is a picture of the bag. (the QR code is a number “181024202132” which I thought might be a phone number but isn’t.  It also doesn’t match anything in google, so i’m not sure what it is.

It also has a picture which says the LCD has one of several different controllers (and after digging in I know for a fact that two of mine were made by Raydium and are not on the list)

The first thing I did was try to use the MCUFRIEND_kbv library to see if the screens worked.  The first board identified as ID=0x9403 and did not work.  Apparently, the tool just spits out the ID if it doesn’t know it, which it did not.

One of the boards identified as ID=0x6814 worked perfectly, and one had a blue cast to all of the screens.  The crazy part is the two boards that identified as ID=0x6814 had different PCBs.  According to the comments in the MCUFRIEND_kbv.cpp ID=0x6814 is an RM68140 and ID=9403 is unknown.

Next, I started down the path of trying to figure out what the controllers were by using register reads.  David Prentice (the guy who wrote/maintains the MCU Friend_kbv Arduino library) has an absolute ton of responses on the Arduino forum trying to help people figure out what their shield is.  He asks them to post the register report from his example program LCD_ID_readnew which is included as an example in the library.

When you look at these LCD controllers they all have some variant of “Read ID” which responds with 1-6 bytes.  The basic idea of this program is to look at what bytes are returned to try to identify the controller.  Here is an example of what I got when I ran the LCD_ID_readnew program on my shields:

The key thing to see in this output is the register 0x04 which says 54,80,66 which identifies this as a Raydium RM68140 LCD controller.  Here is a snapshot from the data sheet.

After digging some more, I decided that it is super ugly out there, as you find that there are a significant number of LCD controllers that are clones, copies, pirated etc… and that they all present themselves differently.  And, in hindsight I think that this is the reason that my ILI9341 from the previous article doesnt quite work correctly.

The next thing that I did was try out the startup code that MCUFriend_kbv generates.  I used the same technique from PSoC 6 + Segger EmWin + MCUFriend 2.4″ Part 1 and spit out the startup bytes.  Here they are:

Well, things still aren’t quite right, so for some strange reason, I keep going and try to use the startup code from the web.  In order to make it work I translate

Earlier I told you that I much preferred to use the more compact startup code.  In order to match this, I decided to add a new code “0xDD” which means delay.  (I hope that there are no controllers out there that use 0XDD).  Here is the updated function:

At this point I have spent a frightening amount of time figuring out how these screens work.  Although it has been a good learning experience, I have generally decided that using unknown displays from China with LCD drivers of questionable origin is not worth the pain of trying to sort out the interface.  Beyond that:

I changed the Adafruit libraries for TFT: GFX , TFTLCD and TouchScreen. I join all in this one library, the library SPFD5408, to avoid problems with duplicate libraries and enables also have the original library Adafruit ready for use in other projects with another TFT hardware.

The new line of 3.5” TFT displays with IPS technology is now available! Three touchscreen options are available: capacitive, resistive, or without a touchscreen.

This article explains how can we leverage Full color 3.5” 480 *320 TFT LCD with Arduino UNO, which is one of the component to display the information with required size, font, color and to use the same as touch screen for input.

Display brilliant colors on the Displaytech 3.5 inch TFT LCD module! This LCD display has 320 x 240 RGB resolution and uses the NewVision NV3035C single chip digital driver. The TFT driver IC supports 16M colors allowing for a range of hues to be displayed and can also support up to 22 different types of input video formats within RGB, CCIR656, and CCIR601 video formats. The 3.5” TFT is available with a touch screen panel in either resistive (single-finger or stylus pressure) or capacitive (five-finger, multi-gesture) touchscreen technology.