what is the actual input/output of 2x16 lcd display?
Its all in the datasheet.
The Board helps those that help themselves.
its stated that lcd using 5v input/output
can i use lower voltage
like 3 or 4.5v?
As Steve said, it is in the data sheet of your particular device.
As a general rule, the 5V types will work with 3V3 if you provide a -ve contrast voltage. 4.5V will be fine with 0V contrast voltage.
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