topic Re: using lcd in opposite direction in LPC Microcontrollers

using lcd in opposite direction

lpcware — Wed, 15 Jun 2016 18:58:06 GMT

Content originally posted in LPCWare by askar on Sun Jun 01 22:54:29 MST 2014
hi,

for some reasons, we want to use 4.3 inch TFT LCD in opposite direction.
i know that we must control frame-buffer in opposite direction, but if we use
hardware cursor, would we have any problem in moving cursor?
or every time we can set cursor X and Y to our needed position?

Best regards,

Re: using lcd in opposite direction

lpcware — Wed, 15 Jun 2016 18:58:07 GMT

Content originally posted in LPCWare by mc on Mon Jun 02 07:25:10 MST 2014
Hi Asker,
I do not know what do you mean by opposite direction,however you can always synchronize cursor with frame synchronization pulse. There is a bit in Cursor Configuration Register(CRSR_CFG),which can be set. You always know cursor X and y Position in cursor X,Y position register(CRSR_XY).

Re: using lcd in opposite direction

lpcware — Wed, 15 Jun 2016 18:58:07 GMT

Content originally posted in LPCWare by askar on Mon Jun 02 21:53:36 MST 2014
Hi mc,

Thank you for your answer,
I mean that we must rotate LCD 180 degrees and then install it in our case.

Best Regards,

Re: using lcd in opposite direction

lpcware — Wed, 15 Jun 2016 18:58:08 GMT

Content originally posted in LPCWare by Martin84 on Tue Jun 03 00:05:17 MST 2014
Are you using emWin? Look in the emWin-manual. There is explained how you could easily change display orientation.

Regards and good luck ;-)

Martin

Re: using lcd in opposite direction

lpcware — Wed, 15 Jun 2016 18:58:09 GMT

Content originally posted in LPCWare by askar on Thu Jun 05 22:47:34 MST 2014
Hi Martin84,

Thanks for your reply, no we do not use emWin. we will control the framebuffer by ourselves.

Best regards,

Re: using lcd in opposite direction

lpcware — Wed, 15 Jun 2016 18:58:09 GMT

Content originally posted in LPCWare by Pacman on Wed Jun 11 23:39:46 MST 2014
In that case, I'd suggest that you just flip your cursor image and subtract Y from the height of the display. :)

Re: using lcd in opposite direction

lpcware — Wed, 15 Jun 2016 18:58:10 GMT

Content originally posted in LPCWare by Pacman on Thu Jun 12 05:31:55 MST 2014
Thinking a bit more about this, I'd like to ask you some questions (that you do not have to answer here; they're just for your own consideration, before you run into a dead end)...

1: Is it really possible using the LCD controller, to "reverse" each line of the frame buffer ?
2: If you succeed in outputting the last line first and the first line last, are you aware that you need to mirror everything on the display then ?
3: If "taking control of the frame-buffer" means reversing it, so it's upside down; then instead of trying to reverse the frame-buffer; wouldn't it make much more sense to keep the frame buffer as is, and then draw everything inside it upside down ?

(Note: NXP experts might be able to answer question #1; if it is possible, I'd definitely be interested in knowing this).

... On the other hand, if you just mean that you're going to draw everything rotated 180 degrees on the screen; go ahead; I believe that's the best way to do it. ;)

Re: using lcd in opposite direction

lpcware — Wed, 15 Jun 2016 18:58:10 GMT

Content originally posted in LPCWare by askar on Fri Jun 13 20:25:12 MST 2014
Hi Pacman,

Thanks for your reply,
we have our own fonts designed in English and non-English languages also many icons and images
with different wall-papers that are designed and used. so we can not re design those to be reversed.
only with reverse processing in frame-buffer, we can show above items correctly on LCD.
I think there will be no problem in reverse processing of frame-buffer.

Best Regards,

Re: using lcd in opposite direction

lpcware — Wed, 15 Jun 2016 18:58:11 GMT

Content originally posted in LPCWare by Pacman on Sat Jun 14 10:58:52 MST 2014
You don't need to re-design the fonts and images.
Of course you can process them while outputting them to the screen, however, in most cases, it will pay to prepare them for display on the microcontroller.

Eg. Make an optimized version of the original files; the optimized version are all pre-rotated by your development computer.
Since the data is pre-rotated, the microcontroller will not have to spend a lot of CPU-time rotating them before outputting the images, and the user-experience willl be much better.

For all kinds of applications, I always recommend optimizing your data, so the data is laid out in a way that is easy for the CPU (microcontroller in this case) to process the data. Eg: Make sure the microcontroller does as little work as it can; it likes being lazy. ;)