Experience-based recommendations to test the brains that drive the devices.
In essentially every embedded system there is some sort of product testing. Typically there is a list of product-level requirements (what the product does), and a set of tests designed to make sure the product works correctly. For many products there is also a set of tests dealing with fault conditions (e.g., making sure that an overloaded power supply will correctly shed load). And many companies think this is enough, but I’ve found that such tests usually fall short in many cases.
The problem is that there are features built into the software that are difficult or near-impossible to test in traditional product-level testing. Take the watchdog timer for example. I have heard in more than one case where a product shipped (at least one version of a product) with the watchdog timer accidentally turned off. Just in case you’re not familiar with the term, a watchdog timer is an electronic timer that is used to detect and recover from computer malfunctions. During normal operation, the computer regularly restarts the watchdog timer to prevent it from elapsing, or “timing out”. (Wikipedia)
How could this happen? Read more here.