Arduino Development for OSX and iOS (2015)
5. Debugging Arduino Logic
5.2 Reviewing Logic Tools
Basically, there ara many tools which can be used to measure signal input/output on Arduino boards. The following is a list of noted tool.
· Saleae, https://www.saleae.com
· Bus Pirate, http://dangerousprototypes.com
· Ika Logic, http://www.ikalogic.com
Normally these tools are not cheap.
You also can buy cheap tools from http://www.dx.com . It's a clone Saleae tool.