Lpc2000

Check the IO levels on the LCD and the minimum output high level on the
2114.  The odds are good that you can directly connect the LCD to the
'14 directly with no pull-ups.  For example:
 
the VOH min level on the 2148 is V3.3-0.4V or 2.9V MINIMUM...  This is
the lowest output that the LPC puts out for a standard load high.
(Usually it will be closer to 3.3V)
 
I am using a Lumex display with a Samsung controller.  It has a VIH min
of 2.2.  Any input above 2.2 is guaranteed to be an input.  Therefore,
there is 2.9 - 2.2, or .7V of margin on the high side input to the LCD.
 
On LOW, there is usually less of an issue.  The LPC will guarantee that
a zero is below VOL max 0.4V while the Samsung LCD controller requires
input to be less than 0.6V, leaving a .2V margin.
 
 
As for LCD to LPC... 
 
Here the Samsung can output .9 x Vcc or 4.5V max, but guarantees to put
out at least 2.4V.  The 2.4 is plenty to swing the LPC to high - it
requires 2.0V or more.  But if the input goes above 3.3V, the "5V
Tolerant" feature of the LPC kicks in.  I don't know the details, but
generally, you can think of this as a resistor in series with the input,
limiting current, and a protection diode that dumps the excessive
voltage to the 3.3 rail.  
 
So.. Bottom line, with this LCD controller, you just wire it up (making
sure to power the LCD from 5V)
 
Hope this helps.
 
Dan
 

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From: lpc2000@yahoogroups.com [mailto:lpc2000@yahoogroups.com] On Behalf
Of bhimanipankaj
Sent: Tuesday, November 15, 2005 8:49 PM
To: lpc2000@yahoogroups.com
Subject: [lpc2000] LCD interface problem


Dear ARMieessss..

thanks for your replies , but my problem is I want to connect a 5V
interface in traditional way that is 8 data lines and 3 control lines
with LPC2214, now LPC2214 datasheet is saying that all GPIOs are 5V
tolerant so I think I can connect the LCD with Pull Ups on GPIO pins
or can I directly connect the 5V LCD with the port pins.

Thanks 

Pankaj  






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