Disclosed are, inter alia, instantaneously restartable clocks and their use. For example, instantaneously restartable clocks can be used to receive data from another independently clocked subsystem in a manner that removes the possibility of metastability errors. A restartable clocking signal generator, relying on oscillating signals typically generated by a continuous oscillating source, is used to generate a restartable clocking signal which can be asynchronously restarted in response to one or more control signals. In one implementation, an apparatus includes multiple independently clocked subsystems and a clockless sequencing network, with the clockless sequencing network being used to initiate the start of a restartable clock in order to reliably receive and process data between the independently clocked subsystems.