Update logic_analyzer.ino

/* Arduino Due adaptation  by jean-pierre Cocatrix jp@cocatrix.fr
* Use the Due Timer library  https://github.com/ivanseidel/DueTimer
* Sampling rate: 10MHz (or lower)
* Channel Groups: 0 (zero) only
* Recording Size:
* SAM3X8E: 7168 (or lower)
* Noise Filter: doesn't matter
* RLE: disabled (unchecked)
* Trigger unchecked.
* Accurate at 1 Mhz or lower.
* Input ports from 33 to 40 (beware: 3.3 volts max)
* Release: v0.13 June 6, 2014.
*/