Serial IN Pin Question

[Andrei IRL]

Hi Everyone.
Happy new Year to all of ye.
I have a quick question.
Im designing a PCB and planning on leaving SERIAL IN Pin not connected to anything as i will not be using this PCB for programming.
Is it OK to leave this PIN Floating or should i ground it or similar?
Thanks very much.

 

[hippy]

The PICAXE will not operate reliably if the Serial In pin is left floating. We would recommend tying it to 0V via a 10K resistor.

 

[inglewoodpete]

The PICAXE will not operate reliably if the Serial In pin is left floating. We would recommend tying it to 0V via a 10K resistor.

I'd put it a bit stronger than that - the SerIn pin MUST BE TIED LOW, one way or another, for reliable operation.

 

[Andrei IRL]

That's perfect. Exactly what i was after.
Thanks very much.
Andrei.

 

[westaust55]

I have found that using a 100 kOhm resistor as a pull-down when there is no permanent programming circuit installed is sufficient, and will allow connection of a programming circuit such as the AXE029 module later if desired to download a new program in-situ.
http://www.picaxe.com/Hardware/Cables/Breadboard-Cable-Adapter/