Tie-Down Resistors

[nfk]

Is it good practice always to use tie-down resistors on all unused input and output pins to prevent them floating? If so, can I use 4K7's?

 

[BCJKiwi]

I believe the outputs don't matter but unused inputs should be tied low to prevent them seeing spurious inputs and to reduce current draw on the PICAXE.

10k is the usual standard value. - you could always double up the 4k7s.

 

[Michael 2727]

Outputs usually don't require pull - up/downs,
unless you are talking about PC network
cards or RF amplifiers/transmitters etc.

In many cases you can get away with
floating inputs (simple applications )
but if you start having problems with
lockups, glitches or instability especially
in electrically noisy enviroments the use
of pull up/downs resistors on any unused
inputs and extra power supply filtering will
fix 99% of most problems, and good earth
shielding on used input cables also.

Any resistor value between 1K to 150K
should work, 10K is a good all round value.

 

[nfk]

Most helpful - many thanks!