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SV: [Lcdproc] HD44780 problems

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  • From: Dave Liquorice" <allsorts AT (Dave Liquorice)
  • Subject: SV: [Lcdproc] HD44780 problems
  • Date: Thu Aug 28 23:20:02 2003

On Thu, 28 Aug 2003 18:47:31 -0400, Guillaume Filion wrote:

> Just to make sure not to confuse anyone, a pull-up is a resistor
> between a line and a VCC (5V for TTL). A pull-down is a resistor
> between a line and a ground (0V). If I remember correctly, your
> solution was a pull-up.

Most likely. Most (all?) TTL based outputs are open collector, so with
the driver transistor off ( to give logic 1, +5v, on the line) the
output line floats unless pulled up by a resistor.


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