My favorite tool for this is the Saleae Logic[1], but I've had mixed success with the cheaper Bus Pirate[2] as well. [1] http://www.saleae.com/logic http://www

My favorite tool for this is the Saleae Logic[1], but I've had mixed success with the cheaper Bus Pirate[2] as well. [1] http://www.saleae.com/logic http://www.saleae.com/logic [2] http://dangerousprototypes.com/docs/Bus_Pirate http://dangerousprototypes.com/docs/Bus_Pirate