PBasic Code

A

ardali

New member
Hello,
I have been experimenting with graphics LCDs recently and I have PBasic Code ready for:
1. To display 22x32 pixel jumbo digits
2. Font scaling to display text (ASCII 32 to 127) in four sizes.
Anybody interested may use them freely and will find them below.
http://www.osmanardali.com/BasicStamp/LCD.htm
A have a problem however:
A minute or two after download the LCD display fades away. I have two 128x64 displays of the same
brand and both act the same way. They are marked 12864H-2K with KS0107/KS0108 controller set.
Pin configuration and the interface I used are as given in the above link.
Anybody have any ideas what may be happening ?
Thanks,
O.Ardali
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C

cosmicvoid

Master
Measure the voltage on Vo when it is working, and then again when it fades away, and check whether the negative supply is still working. Also, the positive end of your contrast pot should connect to +5 instead of ground.
 
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A

ardali

New member
Thanks for the suggestion. For some reason the negative voltage output is dropping.The measured values are as follows (all with respect to 0 V) :
When the positive end of the pot is connected to 0 V:
Vee starts at -9.4 V ....... drops to -8.0 V
V0 starts at -8.6 V ...... drops to -7.4 V
When the positive end of the pot is connected to +5 V :
Vee starts at -9.2 V ...... drops to -7.8 V
V0 starts at -9.0 V ...... drops to -7.7 V
Both displays give the same readings.
Any ideas ?
Thanks,
Ardali

PROBLEM SOLVED !
Supply Voltage is dropping from 5.02 V to 4.35 V probably due to voltage supply IC is getting excessively hot.
Should have checked as a first thing.
Thanks everyone.
Ardali
 
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