A quality assurance integrated circuit for a print controller is provided. The IC has a memory, a system clock having a ring oscillator for generating a clock signal, clock trim circuitry for trimming the clock signal generated by the system clock and a processor. The processor is arranged to, in response to receiving an external signal, determine the number of cycles of the clock or external signal during a predetermined number of cycles of the external or clock signal, respectively and to output the determined number of cycles to an external circuit, and, in response to receiving a trim value based on the determined number of cycles from the external circuit, store the trim value in the memory and control the clock trim circuitry to trim the frequency of the clock signal generated by the ring oscillator using the trim value.