One or more circular debug buffers can allow terminal output data to be provided from the target system to a host without halting the target system or causing significant delays. One or more circular debug buffers may also allow input (such as keyboard input) to be provided from the host to the target without halting the target system or causing significant delays. Accordingly, communications between the target and host may be performed in real time or near real time. These communications may be used for debugging purposes or more generally, for any purpose, including purposes unrelated to debugging.