Main Board that can catch low voltage events

NETMF & Gadgeteer
1

hi all,
I need a main board that can catch low voltage signals, and raise an event.
I will explain with an example.
I implemented at the Spider-Board, socket 9:
(note: my class implements the abstract class Module)


//configure it to be at interrupt mode:
_socket = Socket.GetSocket(9, true, this, null);
InterruptPort interrupt = new InterruptPort(_socket.CpuPins[3], true, 
Port.ResistorMode.Disabled, Port.InterruptMode.InterruptEdgeBoth);

and then I registered to that pin:


interrupt.OnInterrupt += NativeEventHandler;

and if that pin will get a 3.3v the event will be raised. but with 1.8v the event is unstable.
my question is:
1. is there a main-board that support 1.8v events?

I tried this with the G120 rev2, and it seems to catch events with 1.8v.
2. is it supported at that board? or it is works accidentally, and I can’t rely on it for other G120 boards?

(I’m not sure that the G120 is good for me, I need a board with higher performance.)

2

You can use poll to read voltage from an AnalogIn pin.

3

I did so with the enum:

Port.InterruptMode.InterruptEdgeBoth

analog reading is extremely expensive, analog pin is rare on the board (I need ~6 event-signal reading on one socket) and poll will catch the CPU…

4

@ andre.m

How setting up the resistor is going to help? It just establishes the default state of the port.

The problem is that the threshold is slightly different from one board to another.

@ Matan

Another way would be to use a comparator, but that will require to add some extra circuitry.

5

@ Architect
what is a comparator?
what extra circuitry I will need to add?

6

@ Matan -

See: http://www.allaboutcircuits.com/vol_6/chpt_6/2.html