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looking for GUI solution with 5 inch display


ep.hobbyiest

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Hi,

I was looking for GUI solution last time, But due to other work i suspended this one.

I have Discovery board STM32F411. 

I want to display some temperature and some data. So, I want to use 5 inch with resistive touch.

Not fast refresh required, but screen loading should not be display.

Few screens might be there.

So, I have following doubt.

1. Is SPI interface will be suitable for my application?

2. Which TFT lcd Controller is compatible with STM32 and ugfx i should use?

3. Do i require extra memory if screen's are more than 6? Mostly i will be using Text only. 

 

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1. SPI will be fine provided the display resolution is not too high. The higher the redolution the higher the bandwidth you need to update it at a reasonable speed.

2. On the uGFX website there is a list of controllers that are supported. Any supported controller will work with STM32.

3. You will need RAM for a framebuffer only if your chosen display controller does not have internal RAM for the framebuffer. In practice all SPI and 8 bit parallel controllers will have internal RAM for the framebuffer. 16bit controllers may or may not depending on the controller. 

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13 hours ago, inmarket said:

1. SPI will be fine provided the display resolution is not too high. The higher the redolution the higher the bandwidth you need to update it at a reasonable speed.

That is of course correct. But whenever possible, go parallel. However, if done wrong this can actually be slower than SPI. Have a look at this goodie: 

 

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ohh... yes.

I don't want to face this problem. 

We can go with parallel method(8/16-bit). 

Then which kind of inexpensive lcd's are used here mostly. I tried last time 3.2 inch lcd which got blown out(without making it work). 

following type lcd's i found (Without criteria)

http://www.winstar.com.tw/products/tft-lcd/module/5-tft-lcd.html

http://www.buydisplay.com/default/tft-5-inch-lcd-display-module-controller-board-serial-i2c-ra8875

http://www.buydisplay.com/default/5-tft-lcd-display-module-wvga-800x480-high-resolution-for-mp4-gps

http://www.buydisplay.com/default/lcd-5-inch-display-480x272-tft-module-touch-screen-for-mp4-gps

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14 hours ago, ep.hobbyiest said:

We can go with parallel method(8/16-bit).

Just make sure that you hook it up properly. Don't hesitate to ask if in doubt.

 

All but the second display that you linked appear to only provide an RGB interface. That's not what you want unless you want to / can use the LTDC peripheral of the higher-end STM32 lines.

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yes, right i dont want to use RGB interface board. 

But how about other display 

http://www.buydisplay.com/default/5-tft-lcd-display-module-wvga-800x480-high-resolution-for-mp4-gps

http://www.buydisplay.com/default/lcd-5-inch-display-480x272-tft-module-touch-screen-for-mp4-gps

 

Are they good?

Does anyone interface this/similar display's ?

Do you know any dev board or other board? So, i can test the display and later i can go for my own pcb.

I have discovery stm32f411 board.

 

Edited by ep.hobbyiest
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Is cost the main concern for you and do you have stringent real time constraints? If not - maybe look at other embedded Linux boards such as those from Olimex (a20, a13 etc). These boards offer a huge amount of processing power and memory along with good i/o and various LCD interfaces including direct RGB for a reasonable price and size. I've used the A20 and A13 along with RGB 4.3" and 5" 800x480 LCDs from China alongside uGFX. The BuyDisplays LCDs are pretty good in my experience (have used 2.8" SPI + 4.3" RGB models). Touch screens work fine with uGFX as they use the Linux touch driver included by Olimex in their Debian build. The great thing with these types of embedded Linux boards is you can easily move from testing on your Linux PC to the real hardware with good confidence things will work exactly the same. Yes there are some odd differences, but it's a much easier road in my experience compared with truly dedicated hardware. 

Just an idea in case you are not wedded to the STM32.

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Hi,

Thanks for the great solution.

Cost: I am mainly looking for availability and in that cost. I am not looking for cheaper solution nor more costly.

4.3 inch will work for me.  

I am using STM32 in my project and i never work on linux board before. So, i am preferring STM32 controller. 

I don't have dedicated board to start work on GUI. I have other board, But for beginner it would be better to have working things to get some confidence.

 

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On 5/8/2017 at 01:29, phofman said:

I am working on integrating the inexpensive 4.63" LCD https://www.aliexpress.com/item/4-63-inch-16-9-272-480-TFT-screen-with-Resistance-touch-and-PCB-panel-LCM/32802272563.html with chibios on STM32F103, will report when finished.

That's great. Let me know where i can help. And i will do it parallely  as well.

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I am working on init sequence - trying to reconcile the ugfx driver init sequence (very likely comes from a different device, some registers are not present in ILI9481, e.g. 0xc4) and the sequence supplied by the vendor. By the end of this week I hope to try running the LCD.

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Always try the existing code first before playing with the init sequence as there are commonly things not mentioned in the datasheets. Also sometimes extra code has been added to handle clone chips (which can be very hard to distinguish from the original physically).

Only change the init sequence if it doesn't work for you and even then change it as little as possible to get it to work.

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Hi inmarket, I very much appreciate you help.

This is what I found out. The code was kindly provided by Abhishek in commit  https://git.ugfx.io/dongie/uGFX/commit/b2252bb7bede275461700db9c56b702a93a33982. Please note the ILI9481 or compatible. Abhishek describes his project on his blog https://theembeddedkitchen.net/author/abhishek/page/2 where he says

Quote

... It uses the Renesas R61581 TFT controller, which is an enhancement of the ILITek ILI9481 originally used in such displays (the instruction set is nearly compatible)....

...The R61581/ILI9481 drivers adapted for this board have been contributed by me to the uGFX project....

R61581 datasheet http://www.allshore.com/pdf/Renesas_R61581.pdf shows exactly the codes found in the  existing gdisp_lld_ILI9481.c - 8 parameters of register (ILI9481 has only six), first parameter of 0xc0 has  options in bits 2:0, fitting the 0x03 value (unlike ILI9481 which has zeros there), register 0xc4 (not present in ILI9481). Clearly this is driver for R61581 which is slightly different to ILI9481. Honestly, this has helped a lot to me since now I know how to handle it.

Thanks, Pavel.

 

Edited by phofman
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