An integrated circuit tester includes a quasi-autonomous test instrument for performing an acquisition task. The test instrument includes a state machine, a command stack for storing commands which specify parameters of the acquisition task, an acquisition device having at least one terminal for connection to a pin of the DUT for acquiring a value of a variable from the DUT in accordance with the defined parameters of the acquisition task, and an acquisition memory for temporarily storing acquired values and making the acquired values available after the test. The state machine is responsive to an externally supplied trigger to initiate performance of the acquisition task under control of a clock signal by reading a command from the command stack and to perform the acquisition task in accordance with the parameters specified in the command.