Re: Inputs left floating at the very start

On May 3, 5:37 am, Tomás Ó hÉilidhe <t...@xxxxxxxxxxx> wrote:
In college, I was always told not to leave input pins floating on a
device such as a 74HCT chip. I was told that the device might behave
erratically if any of its inputs are floating.

I have the PIC16F684. One of its inputs goes to the data input of a
shift register, and the other goes to the clock input of the same
shift register.

On the shift regsiter, there's an RC circuit on the master reset with
a charge time of about a microsecond (which is plenty slow enough to
have it set to all zeroes initially).

When the PIC boots up, all of its IO pins are set as inputs initially.
What I'm concerned about though is that shift register's input pins
must be either high or low, so I'm wondering if I'll get erratic
behaviour at the very start because the pins are effectively floating?

If you are driving LEDs with the Shift Registers, what difference does
it make to have random outputs for a few milliseconds? Noboby can
really catch it anyway.
.

Relevant Pages

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