STM32F407ZET6 and 4.3'' 480(RGB)*272 TFT with Touch screen

roythomas · ‎2016-10-03

Posted on October 03, 2016 at 14:43

I have a STM32F407 board and I need to drive 480*272 TFT with touch. I am new to TFT and Graphics.

After some reading/Googling I have decided to use STemWin for the graphics which ST provides free. I plan to start work from a CubeSTM32F4 example with STemwin Hello world example. I plan to use parrellel 6800 interface between LCD and MCU which I belive can be implemented by modifying low level functions in the Cube example.

On going through the examples in CubeF4, it seems to me that other than the simple Hallo world, other examples are implemented on a board with external SD RAM.

So I would like to know weather my hardware and software plan is ok for a decent UI. My TFT LCDS is with built in Driver RA8875 chip. 6800 8/16 bit interface is also available.

My UI is for a machine where I need to do some settings menu, buttons and some parameters display.

Please give some inputs regarding the pros and cons I need to be aware before choosing hardware and software.

Other than the display, the tasks we need to handle in the device is RS485 reception and some control operations which is not at all a huge task compared to UI.

Thanks

#tft #stm32 #lcd #stemwin #cubef4

Tesla DeLorean · ‎2016-10-03

Posted on October 03, 2016 at 17:56

The controller in question has it's own frame buffer, thus doesn't need SDRAM, or 255KB of your SRAM, to paint the screen on each refresh. Your access to the frame buffer will be through the controller, and will be much slower to manipulate and draw on to.

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roythomas · ‎2016-10-03

Posted on October 04, 2016 at 07:13

So having a frame buffer within the LCD controller (RA8875 have Embedded 768KB DDRAM). eliminates the need for a external RAM chip in the MCU board. Is my understanding correct in that case? If I am using the FSMC bus in STM32F407, the access of frame buffer in the LCD driver could be prety fast.right?

So can I belive my hardware choice could be reasonable for a decent UI?

mark239955_stm1 · ‎2016-10-04

Posted on October 04, 2016 at 13:06

The datasheet claims the RA8875's parallel bus can run at 20MHz. If that holds true, you will be able to write data to the frame buffer at up to 40MB/s using a 16-bit bus, the 407's FSMC and (presumably) DMA.

You should find the performance to be... adequate.

Walid FTITI_O · ‎2016-10-04

Posted on October 04, 2016 at 14:35

Hi thomas.roy.001,

You would check the

http://www.st.com/content/ccc/resource/technical/document/application_note/54/c9/95/42/8c/0b/43/69/DM00089670.pdf/files/DM00089670.pdf/jcr:content/translations/en.DM00089670.pdf

''Getting started with STemWin Library''. You may find response to your questions.

-Hannibal-