Stalker Digital Input Voltages

What is the maximum voltage that the Stalker analog and digital inputs can accept? I made a shield that uses a TLC3702CP comparator chip to produce a 0 -5 vdc square wave signal. The board works good but when I connect the output to digital channel 3 (Interrupt 0) the signal is pulled down from 5 vdc to 3.8 vdc. I tried the shield and sketch on a Arduino Duemilanove and it worked with no problems.

From a earlier thread I know the output is 3.3 VDC but did not think it would affect the input. I tried a 470 ohm resistor between the comparator and Stalker and that kept the output signal of the comparator at 5 vdc with little drop on the Stalker side below the 3.8 vdc as seen without the resistor. If the Stalker can only accept 3.3 vdc signals, is there a safe way to connect 5 volt inputs?

Thanks in advance.

The Stalker’s working voltage is 3.3V. If you want to send 5V signal to it, you’d better add two divider resistances to divide voltage from 5V to 3.3V.

All the best,