Continue to Site

Welcome to EDAboard.com

Welcome to our site! EDAboard.com is an international Electronics Discussion Forum focused on EDA software, circuits, schematics, books, theory, papers, asic, pld, 8051, DSP, Network, RF, Analog Design, PCB, Service Manuals... and a whole lot more! To participate you need to register. Registration is free. Click here to register now.

VGA Driver rate using GPIO

Status
Not open for further replies.

alzomor

Advanced Member level 2
Joined
Jun 9, 2005
Messages
674
Helped
39
Reputation
78
Reaction score
8
Trophy points
1,298
Location
Germany
Activity points
6,406
Hi

I am devloping a LCD VGA driver using GPIO's
I need to ask is it possible to drive the LCD at lower refresh rate?
for example my LCD is 70Hz, can I drive it at 15 or 30 Hz?

Regards
Hossam Alzomor
 

Yes, you can.
I drive LCD at 25Hz, no problem.

But i think you drive LCD with GPIO is not possible. You can use FPGA or CPLD to drive LCD.
 
Thanks Jiangfux,

If you are using 25Hz with 800*600 resolution the total number of pixels per second is 12MPixel and if the processor is running at 24Mhz we have two instructions per Pixel and if the processor is running at 24Mhz we have 4 instructions per Pixel.
am I right?

May you give me some information about your timing?

Regards
Hossam Alzomor
 

alzomor,
If LCD is run at 25Hz with 800 * 600 resolution, the total number of pixels per second is 12MPixel, but the clk of the LCD shoule more than 12MHz, because the blank at start of line and end of line, may be 18MHz.
If you use gpio to drive LCD, processor running at 24MHz, two instructions per pixel, but your program shoud do something else, E.X, fetch pixel data, do loop instructions, and so on.
As i mentioned before, you can use FPGA + SDRAM, or use CPU with LCD driver(BF531 with ppi).
 

May you kindly give me some information about the timing for driving the LCD at 25MHz as in your project.
Sorry for my poor english. I think you should get the timing for driving the LCD in datasheet. Timing of LCD is different from one to another.

- - - Updated - - -

Here is timing of my LCD.
20131123203823.jpg20131123203852.jpg
 
Status
Not open for further replies.

Similar threads

Part and Inventory Search

Welcome to EDABoard.com

Sponsor

Back
Top