3v to 5v level translation

From: Scott Miller (scott_at_3xf.com)
Date: 02/09/05 

Date: Wed, 9 Feb 2005 09:18:56 -0800

I'm connecting a 5-volt HD44780 LCD controller to a 3-volt microcontroller.
I'd planned to use a level translator IC, but I just switched to an MCU with
5-volt tolerant inputs. Actually, I don't need inputs - just 6 outputs. My
question is this - assuming the slew rate is acceptable, is there any reason
I can't just connect each I/O line to a pullup to 5 volts, set the port to
all 0's, and then use the data direction register to switch between
high-impedance input mode and output to control the 5-volt signals?

Seems to me like it should be fine, but I can't recall having seen it done
that way before.

Thanks,

Scott

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