Yes. You have to have a common ground. /Ake bhimanipankaj wrote: > Dear all, > > If I am connecting 5V lcd directly with lpc2214, should I common all > the grounds for 5V for LCD supply as well as 3.3V for controller supply. > > Pankaj > > --- In lpc2000@yahoogroups.com, "Dan Beadle" <dan.beadle@i...> wrote: > > > > 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 > > > > > > _____ > > > > 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 > > > > > > > > > > > > > > SPONSORED LINKS > > Microprocessor > > > <http://groups.yahoo.com/gads?t=ms&k=Microprocessor&w1=Microprocessor&w2 > <http://groups.yahoo.com/gads?t=ms&k=Microprocessor&w1=Microprocessor&w2> > > =Microcontrollers&w3=Pic+microcontrollers&w4=8051+microprocessor&c=4&s=9 > > 3&.sig=tsVC-J9hJ5qyXg0WPR0l6g> Microcontrollers > > > <http://groups.yahoo.com/gads?t=ms&k=Microcontrollers&w1=Microprocessor& > <http://groups.yahoo.com/gads?t=ms&k=Microcontrollers&w1=Microprocessor&> > > w2=Microcontrollers&w3=Pic+microcontrollers&w4=8051+microprocessor&c=4&s > > =93&.sig=DvJVNqC_pqRTm8Xq01nxwg> Pic microcontrollers > > > <http://groups.yahoo.com/gads?t=ms&k=Pic+microcontrollers&w1=Microproces > <http://groups.yahoo.com/gads?t=ms&k=Pic+microcontrollers&w1=Microproces> > > sor&w2=Microcontrollers&w3=Pic+microcontrollers&w4=8051+microprocessor&c > > =4&s=93&.sig=TpkoX4KofDJ7c6LyBvUqVQ> > > 8051 microprocessor > > > <http://groups.yahoo.com/gads?t=ms&k=8051+microprocessor&w1=Microprocess > <http://groups.yahoo.com/gads?t=ms&k=8051+microprocessor&w1=Microprocess> > > or&w2=Microcontrollers&w3=Pic+microcontrollers&w4=8051+microprocessor&c= > > 4&s=93&.sig=1Ipf1Fjfbd_HVIlekkDP-A> > > > > _____ > > > > YAHOO! GROUPS LINKS > > > > > > > > * Visit your group "lpc2000 > > <http://groups.yahoo.com/group/lpc2000> " on the web. > > > > * To unsubscribe from this group, send an email to: > > lpc2000-unsubscribe@yahoogroups.com > > <mailto:lpc2000-unsubscribe@yahoogroups.com?subject=Unsubscribe> > > > > * Your use of Yahoo! Groups is subject to the Yahoo! Terms of > > Service <http://docs.yahoo.com/info/terms/> . > > > > > > _____ > > > > > > > > > > [Non-text portions of this message have been removed] > > > > > > > > > SPONSORED LINKS > Microprocessor > <http://groups.yahoo.com/gads?t=ms&k=Microprocessor&w1=Microprocessor&w2=Microcontrollers&w3=Pic+microcontrollers&w4=8051+microprocessor&c=4&s=93&.sig=tsVC-J9hJ5qyXg0WPR0l6g> > Microcontrollers > <http://groups.yahoo.com/gads?t=ms&k=Microcontrollers&w1=Microprocessor&w2=Microcontrollers&w3=Pic+microcontrollers&w4=8051+microprocessor&c=4&s=93&.sig=DvJVNqC_pqRTm8Xq01nxwg> > Pic microcontrollers > <http://groups.yahoo.com/gads?t=ms&k=Pic+microcontrollers&w1=Microprocessor&w2=Microcontrollers&w3=Pic+microcontrollers&w4=8051+microprocessor&c=4&s=93&.sig=TpkoX4KofDJ7c6LyBvUqVQ> > > 8051 microprocessor > <http://groups.yahoo.com/gads?t=ms&k=8051+microprocessor&w1=Microprocessor&w2=Microcontrollers&w3=Pic+microcontrollers&w4=8051+microprocessor&c=4&s=93&.sig=1Ipf1Fjfbd_HVIlekkDP-A> > > > > ------------------------------------------------------------------------ > YAHOO! GROUPS LINKS > > * Visit your group "lpc2000 > <http://groups.yahoo.com/group/lpc2000>" on the web. > > * To unsubscribe from this group, send an email to: > lpc2000-unsubscribe@yahoogroups.com > <mailto:lpc2000-unsubscribe@yahoogroups.com?subject=Unsubscribe> > > * Your use of Yahoo! Groups is subject to the Yahoo! Terms of > Service <http://docs.yahoo.com/info/terms/>. > > > ------------------------------------------------------------------------ > -- --- Ake Hedman (YAP - Yet Another Programmer) eurosource, Brattbergavägen 17, 820 50 LOS, Sweden Phone: (46) 657 413430 Cellular: (46) 73 84 84 102 Company home: http://www.eurosource.se Kryddor/Te/Kaffe: http://www.brattberg.com Personal homepage: http://www.eurosource.se/akhe Automated home: http://www.vscp.org [Non-text portions of this message have been removed]
Message
Re: [lpc2000] Common ground!!!
2005-11-16 by Ake Hedman, eurosource