Graphical display

[chandu13]

Hi

Presently aim measuring pressure and displayed on the LCD display.
Now I have to replace the LCD with graphical LCD.
Please give me some information about graphical display
Presently aim using 89C51 with keil software.
Wither 89C51 is suitable for Graphical display.


What is the difference between the LCD and graphical LCD.
How to program the graphical LCD.The program is same as LCD or different.
Please give information about graphical displays.

Regards
chandu

 

[i_build_stuff]

Text displays usually have a driver built-in that lets you stream character codes through a serial connection. These are nice because they require very little data from the controller.

With graphical displays, you're sending pixels instead. The format can change depending on the display you're using. Normally, it "scans" the screen like a VGA monitor (left to right, top to bottom), but it splits the screen into two halfs. Each byte you send in writes four pixels on the top half and four on the bottom half (to cut flicker). This means you need to use some logic or software to dump your framebuffer in order.

Is the 89C51 a Microchip PIC product (it sounds like one)? If so, it's probably fast enough to dump memory out onto a small screen that uses the format above, but might not have time to do anything else in between (like draw the text / graphics on your framebuffer). It really depends on your application and how big the screen is going to be...

 

[chandu13]

Thank s for the reply

For graphical display i need any software? Or i have to write program in controller.

Please give more information about “how to use the graphical displays”

And related internet sites.

Regards
chandu

 

[Oznog]

I have to contradict i_build_stuff here.
No hobbyist I know of scans out pixels due to the difficult hardware requirements. We use LCD modules with a built-in controller, most often the T6963, less commonly the SED1330.

These controllers use a data bus. In general, you put 8 bits of command on the data bus, pull the command pin, then follow it with 8 bits of data and pull the write_data pin. Most commonly you're writing 8 bits of screen pixel data or setting the graphical address pointer here. Well, read your controller spec for a real description.

There are many examples of code which talks to the T6393 controller, you may need to adapt the parameters for say your particular screen size. I recommend you write your own actually. It's not rocket science.

 

[ikalogic]

Is the 89C51 a Microchip PIC product (it sounds like one)? If so, it's probably fast enough to dump memory out onto a small screen that uses the format above, but might not have time to do anything else in between (like draw the text / graphics on your framebuffer). It really depends on your application and how big the screen is going to be...

nope! far from being a pic product nor an AVR core.. its an ATMEL product, with a 8051, 12 instructions per cyle processor. can run up tp 33Mhz


However, 8051 is switable for driving LCDs for sure, wether it is Alphanumeric or Gfx.

I also agree with Oznog, all the LCDs i worked with had a built-in powerfull micro processor..


Chandu, the first thing you need is the datahseet for your LCD. its not more difficult than an Alphanumeric lcd, but there are differences that you need to find through the datahshet

 

[dratomic]

8X51 family

If you're really interested in doing graphics in real time
then consider the Dallas / Maxim Drop-in series. At 1
clock per instruction these things blaze.

 

[eblc1388]

with a 8051, 12 instructions per cyle processor. can run up tp 33Mhz

If so, it must be the fastest processor in the whole world.

 

[Nigel Goodwin]

If so, it must be the fastest processor in the whole world.

I thought the 8051's were the other way?, 12 cycles per instruction? - that entire 'family' of devices (8008, 8080, Z80 etc.) have always required many cycles per instruction - which was why a 6502 at 1MHz was as fast as a Z80 at 8MHz.

 

[Oznog]

You wanna blaze, the dsPic33F series is 40MIPs and it has some really efficient instructions. It's a 16-bit core.

Awhile back I saw the real potential to use the DMA controller to drive an LCD without a controller, just some external RAM. However, I later found that Microchip failed to dual-port the LAT or PORT registers so you couldn't use the DMA controller to automatically read or write them.

I was bummed and pissed.

 

[ikalogic]

If so, it must be the fastest processor in the whole world.

oooooops yes, 12 cycle per instruction! sorry!

 

[dratomic]

Dallas / Maxim

The Dallas/Maxim chips are single clock per instruction
and can provide an effective speed of 99mhz. Blazing!
You do have to make sure of your timing though when
using older code with timing loops ect.....