LCD driving trouble
Andre email (remove spam text)
Hi all !
I«ve been working on a CPU used to control a high teperature high pressure chamber based on a 16C622A.
It has a LCD display (16x1) been drived using nibbles instead of 8 bits words. Unfortunatly I have no more free I/O pins to use.
The problem is as follow:
1. When I first turn the CPU ON everything goes right. The LCD shows the message it was programed to show.
2. If I turn the CPU OFF and not after one or two seconds back to ON again the LCD shows anything but the message it was programed to show.
3. If I wait a little bit more (5 sec.) before turning the LCD back to ON again everything goes right.
4. If I turn the CPU OFF and back to ON two times without wait all goes ok.
I am sening the data without using the LCD R/W pin. The data is sent to the display and the program waits it to stabilize before sending the next 4 bits.
Any comments or sugestions are welcome !!!
See also: www.piclist.com/techref/io/lcd/pic.htm?key=lcd
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