Go Down

Topic: ***Fixed*** Ks0108 128*64 -> no gfx showing + pictures Atmega 2560 (Read 3 times) previous topic - next topic

spikee

if you use +5V instead of GND there will be smoke out of the lcd :P

bperrybap


if you use +5V instead of GND there will be smoke out of the lcd :P


Huh? I'm not sure what you are thinking.

I am talking about what connects to the pot leg.

There was earlier discussion in this thread that Don brought up, about what is opposite VEE on the pot.
Should it be +5v or GND? That was the question.
My response was that ground should work but nearly all the glcd data sheets show using +5v
which is why I recommended wiring up the to pot leg to +5v vs ground like the glcd documentation
shows.

The data sheet that you posted a link to shows using ground on the pot leg.

If this is not clear or you are not understanding this, please ask more questions.

--- bill


Grendel

I also have the Satistronics 128x64 GLCD screen.  Everything worked for me except I have to use a 1M ohm pot for contrast.  20K was not sufficient.  The impedance of the pot after correctly adjusting it is 680k ohms.  My pot is connected from pin 18 (VEE), wiper to pin 3 (contrast), and the 3rd leg is connected to GND (0v).  Not sure why 20K doesn't work for me but it's no biggie.  I only post this in case someone else has a similar problem.

floresta

Quote
20K was not sufficient.
The 20 K pot was either defective or it was not connected properly.  The overall resistance of the pot has essentially no effect on whether it will work for this purpose or not.

Don

liudr


Quote
20K was not sufficient.
The 20 K pot was either defective or it was not connected properly.  The overall resistance of the pot has essentially no effect on whether it will work for this purpose or not.

Don


I agree, I tend to think the 20 K pot may be bad too. A possible scenario to have broken it is to have connect top pin to 5V and the middle pin to GND, while the wiper is very close to the top, literally having a few ohms between 5V and GND. That could exceed the power rating of the pot and burn the internal "wire" open, resulting in a bad pot. Does the above speculation make some sense to someone?

Go Up