4.3" TFT, no chipset specified?  - Page 1
Forum section: electronics / projects

author: julian1
author_rank: Frequent Contributor
timestamp: December 07, 2021, 10:32:35 pm
content: Looking at the following TFT display, they have great documentation, and the flex connector exposes multiple programming interfaces (parallel, spi) which is nice.https://www.buydisplay.com/low-cost-lcd-display-4-3-inch-arduino-spi-i2c-tft-touchscreen-800x480https://www.buydisplay.com/download/manual/ER-TFTMC043-7_Datasheet.pdfBut why don't they state the chipset (ilixxxx, ssd1963 etc)? The doc does mention the capacitive touch ic - eg. XPT2046. Knowing, the chipset can make it easier to use boilerplate code - eg. for init sequence.

author: ataradov
author_rank: Super Contributor
timestamp: December 07, 2021, 11:01:52 pm
content: Ask them. This is unusual. Typically they have the display datasheet and a controller datasheet. Here it is a combined datasheet. It is possible that it is some sort of a custom controller that they don't want to name as a separate part number. Unlikely, but who knows.Edit: in the example source code they call it ER5517, so it does look like a custom controller. And touch controller is XP2046 according to the same driver file.

author: SiliconWizard
author_rank: Super Contributor
timestamp: December 07, 2021, 11:12:32 pm
content: The datasheet itself contains information about how to control the LCD. So, read the datasheet of the module. It's an Eastrising module as far as I can tell, and it uses a custom controller that is also from Eastrising. So you won't find it documented elsewhere. It's none of the regular controllers. As can be seen in the source code, it's apparently an ER5517, which is an Eastrising reference. There is no separate datasheet you can find (I looked...) But normally, everything is contained in the datasheet you linked here.You can also download the provided source code (Arduino and 8051 stuff) to extract/study functions that drive the module's controller.

author: IDEngineer
author_rank: Super Contributor
timestamp: December 08, 2021, 08:09:20 am
content: That's a surprisingly powerful display chip. It supports polygon primitives, etc. Not just your basic "specify every pixel" memory map.

author: DavidAlfa
author_rank: Super Contributor
timestamp: December 08, 2021, 01:54:44 pm
content: Wow, this driver is nuts!Ellipse/polygon drawing with filling support, chroma blending, color expansion, block transfer engine, internal fonts, support for custom fonts in SDRAM and external spi cgrom...!The embedded 32MBit SDRAM can store 3.6 layers of 840x480 24ppp, a lot of content can be stored, ready to be shown when needed.

author: amyk
author_rank: Super Contributor
timestamp: December 08, 2021, 02:36:28 pm
content: It's either RA8871M or LT7381, based on Googling a few specific sentences from the datasheet. Probably the latter since "supports the function of drawing Circles and Ellipses" shows up in both this display's datasheet and the LT7381's, with a lot of copy-pasted material (a lot of controller datasheets are copy-pasted from each other.) LT768x is another possible match.

author: fearless
author_rank: Contributor
timestamp: December 10, 2021, 05:15:15 am
content: FWIW, I'm working with the 7" version of this display:https://www.buydisplay.com/low-cost-arduino-7-inch-touch-screen-800x480-i2c-lcd-tft-spi-displayAnd it's pretty great. I haven't exercised all of its many features -- in my case, it's sufficient to write .bmp files from the host processor into the several layers in the display, then make each layer visible when requested. And then you can overly the bitmaps with native graphic primitives (i.e. rectangles and ellipses) to animate the images.Switching layers is nearly instantaneous, as are the native graphics primitives. As for transferring the 800 x 480 x 2 byte bitmaps from an SD card to the display, I've got it down to 3 seconds per screen. That's on a SAMD21 running at 48MHz and a 12MHz SPI bus -- the system is limited by processor speed, not by the display. (I take delivery on a SAME70 with a 300 MHz clock and fast MMC interface in the next day or two, so it should be able to write the bitmaps much faster.)If anyone else is going this route, the code examples on the web site are easier to understand than the documentation. I got a lot of mileage by extracting the library files from the Arduino projects and incorporating them into my IDE, then optimizing where needed.- ff