I am trying to interface JHD12864E graphic LCD with an ATmega32 controller. I simulated it in proteus using the LGM12641BS1R model. Both are KS0108 compatible so I thought it should work. I have written some code using the procyon avr library. The only change I did was to modify the code for a active high RST signal (in place of an active low signal as on LGM12641). For that I changed the function glcdreset and added a not in the if condition. Also in the proteus model I added a not gate primitive before the RST signal. So now I guess my model and the actual chip are compatible. And it works too, in simulation. But when I burn it on the ATmega32 chip I do not get anything except the LED backlight. I have double checked the wires and they are in order. What else may be the problem?

  • \$\begingroup\$ Probably a simulator problem. Have you asked Proteus about it? \$\endgroup\$ Commented Jan 15, 2013 at 9:32
  • \$\begingroup\$ how do I ask proteus? Also, since the lcd is compatible with the ks0108 controller, it should work. \$\endgroup\$
    – Rick_2047
    Commented Jan 15, 2013 at 9:36
  • \$\begingroup\$ I think the issue is common ground or common anode problem. Check it up. \$\endgroup\$ Commented Jan 15, 2013 at 9:54
  • \$\begingroup\$ @sandundhammika if I connect the LCD all the dots are active as if its high contrast. So I guess common ground or common anode problem is not there. \$\endgroup\$
    – Rick_2047
    Commented Jan 15, 2013 at 10:01
  • \$\begingroup\$ @Rick_2047 All dots active? Do you have contrast control working yet? \$\endgroup\$ Commented Jan 15, 2013 at 10:09

1 Answer 1


The same problem was with me with 16x2 character LCD. I recognized that Proteus runs the code even without 'pot' connected to Vo pin. Try connecting the 10k pot to Vo pin and calibrate to provide nearly ground potential...


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