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I have a display and in the datasheet it says that it need "Negative voltage for LCD driving" on the VO pin?
What does that mean? can i connect it like itīs discribed in the PBP manual?
Datasheet
http://www.vtronic.com.cn/products/images/VT162B-B.pdf
What happens if you do connect the Contrast pin as per the manual?
I donīt know, i haveīt tryed yet.
Do you think it will work whitout a negative voltage?
Well it's not going to harm it.
You worry about providing a negative voltage if it doesn't work through conventional ways first.
If you do need a negative voltage, then if you have a PIC that can give you HPWM, we can easily generate one from that with a few components.
Hi,
3 pin on LCD is normally tied to GND. negative supply is need by extrem contrast or low temperatures.
You can help with PWM from PIC. see Attachment
Samo
Fredrick, You can also use the -9 volts from an RS-232 interface ic if you are using a serial interface to your computer for boot loading.. I do this quite often.
Dave Purola,
N8NTA
I use a USB interface with a FTDI RS232 chip on the board.
I will try first and just connect it to GND and se whatīs happends.
Just connect the Vo to GND doesīt work, all the "pixels" on the display are showing but no text.
I think this display needs negative voltage for LCD driving.. :(
You have problem in software. When show all pixels on display then is contrast ok. Check your data signal
Try connecting as the manual shows with a pot as a voltage divider, then try adjusting until the display is clear.Quote:
Originally Posted by Fredrick
The display i working now but itīs slow.
The problem was that i have forgot to connect the "Enable" signal, i checked the connections severel times before i notice that. I have must been tired :o
Do not tell anyone, but I made a similar mistake awhile back.:DQuote:
Originally Posted by Fredrick