Go to page on main NoviceGuard site with list of all pages.

Go to main page of NoviceGuard site.

This page named "TransTwelveWayChangeDevices" to say the following...

It is a page with a transitory existance. In due course, it will be subsumed into other pages.

It is about an important aspect of using things via the TwelveWay connector of the NoviceGuard.

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Two things need to be remembered:

a) The twelve way connector is the most advanced part of the NoviceGuard. It is not "hard" to use, but novices should have done quite a bit with the simpler elements first.

b) This page, and the approach suggested here, is a work in progress. In due course, I intend to modify these instructions to move us on to something which will be easier for the novices, and at the same time make it harder for inadvertant mistakes to do harm to the Arduino.

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Here's the electronics behind the rules I am about to lay down...

The different "lines" (connections to the Arduino) present on the twelve way connector can be set to be inputs or outputs.

The different things you might connect to the twelve way connector will have "input" or "output" circuitry going to the pins.

It is A Very Bad Thing to connect a line set up as an output to a circuit which is a "send stuff to the computer" type circuit. (I.e. something that should only be connected to a line set up to be an input.) You will sometimes Get Away With It... but that's not a good plan for your SOP.

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So... here are the rules....

If you are re-powering a system... Arduino+program+NoviceGuard+things plugged into it... after turning it off earlier, and you have made not changes to the system, then that's no problem. Power up, power down, as often as you like.

If you are making changes in an existing system, just to the software, that's no problem... although you must as ever be careful that the data directions specified for the different lines are appropriate to the circuits connected to them.

If you want to change the connected hardware (and the signal on any pin will change type, or you are not sure what program was last put into the Arduino....

... here is what I suggest.

Before applying power, disconnect the current hardware.

Connect JUST the Arduino and Noviceguard to the development machine. (You can leave any daughterboards in place.)

Re-program the Arduino for whatever you are going to connect via the twelve way connector.

Power the Arduino down, or not, as the nature of what you are going to connect would suggest wise. (If in doubt, power down. It isn't hard, after all! (You can leave the "big" computer running though all of this.))

Re-power the Arduino + NoviceGuard + whatever's connected via twelve way connector.

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If you pull an old Arduino off the shelf, one you haven't used for a while, one lacking a tag saying how it is programmed (!)... use the procedure just outlined. It is NOT safe to plug it in, and "see if it works". If it doesn't. bits of Arduino or twelve way connector board may never work again.

Go to page on main NoviceGuard site with list of all pages.

Go to main page of NoviceGuard site.