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Dear Friends,
I have just interfaced a lot of devices with c8051f120 (Si Labs) and was doing good but its been quite a long time and i am not able to get graphics LCD 128x64 to work.
I am using 1K pull ups,also how do i execute the status read instruction. It always returns 0x00 on the port,although i change display on / off.
I am not getting any display on it and also dont know if it is executing the instructions i send or not. I have followed the flow as exactly in the datasheet.
All happens is that during power up,all pixels are 1 for abt a milli second and thats it..Sometimes it takes some random instructions and displays random lines..
Pls help..
my guess is that you have 'slope problems'
instead of pull-ups use a 74HCT to convert 3V3 to 5V and use a 74lvc4245 to convert 5v to 3V3. If you have a lot of 3V3 to 5 conversions the 74lvc4245 will do that as well.
Erik
The Application Note from Silicon Labs suggests that Open-Drain and Pull-Ups to 5V will drive a 5V device...
sure, they want to show you that you can do it "on the cheap". I have seen that 'suggestion'.
Resistive pullup equals very slow (in digitral terms) risetimes.
Resistive pullup works just fine for inputs that are not 'slope sensitive' e.g. driving a relay driver, but for clocked devices they spell trouble.
Hi, Thanks for showing your interest..
I used pull ups and got it working quite fine..
Actually i had made a big blunder-- used the wrong datasheet..on which the pins were different..whew!! thanks god atleast i didnt blow up the lcd..it was an old module and the datasheet looked very genuine..anyways it was much fun workin with a graphic LCD...