Model Checking Software for Microcontrollers

A method for model checking of microcontroller code is presented. The main objective is to check embedded C code including typical hardware specific ingredients like embedded assembly statements, direct memory accesses, direct register accesses, interrupts, and timers, without any further manual preprocessing. For this purpose, the state space is generated directly from the assembly code that is generated from C code for the specific microcontroller, in our case the ATMEL ATmega family. The properties to be checked can refer to the global C variables as well as to the microcontroller registers and the SRAM. By this approach we are able to find bugs which cannot be found if one looks at the C code or the assembly code alone. The paper explains the basic functionality of our tools using two illustrative examples.