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Topic: 7"Arduino Touch Screen Shield w/SSD1963,Library for Mega/Due (Read 1 time) previous topic - next topic

capblack

HI all, I bought this LCD and only show when I press reset is like not enable the led.

http://www.buydisplay.com/default/7-inch-arduino-touch-screen-shield-ssd1963-library-for-mega-due

library's UTFT_Demo_800x480 , any help ?

Thanks

PrSaban

You must to add this line on your void setup() :

pinMode(8, OUTPUT);
digitalWrite(8, HIGH);

Because the backlight through your shield is pin 8, so you need to turn up it


PrSaban

I am working with TFT LCD similar yours. And my problem is how to increase the speed of loading image.

Have you loaded an image through SD card?

Can you tell me the speed of loading image?

I use MEGA 2560 board, so the speed of loading is pretty slow. ( 800x480 size is about 3960 ms :(( )

david_prentice

Think about it.    2 bytes per pixel, 38400 pixels.   Even if you were reading the SPI @ 8Mhz with no filesystem housekeeping,    this will take 768ms.   Writing 38400 pixels to the screen will take at least 38ms.

The MEGA2560 can not use USART_MSPI.   So you are stuck with the regular SPI peripheral.

The Arduino SD library,   SPI library,   your TFT library,  ... will all introduce extra time.
3960ms is probably as good as you can get.

If it is important to have fast screen changes,   buy a CPLD display.    You will still have the transfer time from SD card but you can write it to the CPLD's "shadow display"memory.    Then switch the memory instantly.

David.

PrSaban

Hi David,

I bought an SSD1963 [BuyDisplay ER-TFTM070-4V2.1 + Touch] and using MEGA2560 board, but I want to have

fast screen changes.

I can replace MEGA2560 by Arduino Due, but I do not want to change LCD. Can I use SDRAM ?

david_prentice

Yes,  you could copy a whole image to an external DRAM chip or even a Flash memory chip.

A mega2560 would need a tight software loop to transfer the image to the display.  A Due can do it faster.   Possibly using DMA.

ColdTears sell a CPLD version that has onboard DRAM and can do everything in hardware.

You need to put some realistic numbers to your problem.   i.e. what is an acceptable time to switch images?
What size of image?

David.

Bigoldsofty

Do those of you who have used this display know of a similar trick to get the touch screen working?
I have 2 of the display and on the touch screen activates.

Bigoldsofty

After some messing around I have the touch screen working.
Now I need to get the SD card working.  According to the manufacturer we are to use the slot on the shield not the one on the display although the one on the display would be more convenient in my application.  Has anyone used the a software SPI with UTFT library and which one?

Bigoldsofty

I have not reached the point of checking how fast the images load because I am not able to get SD card to work. 
Using the EastRising display from BuyDisplay (TFTM070-4 with AS-SSD1963 shield) the SD Card does not seem to work.  It used pins 44,45,46,47 on the MEGA.

I also have a SainSmart 5" screen on which I finally got the SD Card to work using the SDRaw library.  This one however does not render the colour correctly.  At first test it looked like the red and blue channels were swapped, because a red image appeared blue and vice-versa.  When an image is prepared in Photoshop with the channels swapped it appears the same as on the PC screen.  A very strange effect.

I may now try a CPLD screen if I can find one that will hold up to 10 800x480 images for quick switching and hope I can get that working.

I do have a screen TFT070TN92 which supposedly is a CPLD screen but it causes a short with any of the shields and I'm not able to find a full data sheet on it.

Any suggestions will be gratefully received.

david_prentice

Congratulations.   Most people just say
Quote
it does not work
You have identified your problem i.e. Blue-Red swap.
It is controlled by BGR setting which is one bit in one register  --- normally bit#3 in reg(0x36).

There many Manufacturer settings for colour inversion (Black-White swap),  write directions, panel size, ...
These are generally initialised in setup() e.g. tft.begin()

Once configured,   your program never needs to worry about them again.

David.

ghlawrence2000

If this has been resolved great, but actually the 'problem' with UTFT_SdRaw is users failing to check the examples properly!

There is a 'bit' in the load function for inverse colour, as Henning in his infinite wisdom uses inverse colour in his RAW images, whereas Irfanview generates the opposite..... so I made SdRaw capable of handling either!!

Regards,

Graham
UTFT_SdRaw now included in library manager!! ;) High speed image drawing from SD card to UTFT displays for Mega & DUE.
UTFT_GHL - a VASTLY upgraded version of UTFT_CTE. Coming soon to a TFT near you! 8) Shipping April 1 2016!

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