A method, performed by a Universal Serial Bus Power Delivery circuit, of controlling a Universal Serial Bus Power Delivery System, comprising: receiving, by a transceiver, a message and outputting a digital representation of the message; determining whether at least a predetermined number of initial bits of the digital representation is received by way of asynchronously determining a number of ripples corresponding to said initial bits in the digital representation, wherein the digital representation is a Biphase Mark Code digital representation and marking, by a latch circuit, a beginning comprising a point at which the digital representation has the predetermined number of initial bits; turning on a clock circuit in response to the marked beginning; determining whether the digital representation has ended and marking, by the latch circuit (162, 164, 166), that the digital representation has ended; starting a counter when the digital representation has been marked as ended; determining whether a count value of the counter has reached a predetermined count value; determining whether a digital representation has restarted and comprises the predetermined number of initial bits before the count value of the counter has reached the predetermined count value; and if a digital representation comprising the predetermined number of initial bits has restarted: determining whether the restarted digital representation has ended and marking, by the latch circuit, that the digital representation has ended; and restarting the counter when the digital representation has been marked as ended; if a digital representation comprising the predetermined number of initial bits has not restarted before the count value of the counter has reached the predetermined count value, turning off the clock circuit when the predetermined count value has been reached. receiving, by a transceiver, a message and outputting a digital representation of the message; determining whether at least a predetermined number of initial bits of the digital representation is received by way of asynchronously determining a number of ripples corresponding to said initial bits in the digital representation, wherein the digital representation is a Biphase Mark Code digital representation and marking, by a latch circuit, a beginning comprising a point at which the digital representation has the predetermined number of initial bits; turning on a clock circuit in response to the marked beginning; determining whether the digital representation has ended and marking, by the latch circuit (162, 164, 166), that the digital representation has ended; starting a counter when the digital representation has been marked as ended; determining whether a count value of the counter has reached a predetermined count value; determining whether a digital representation has restarted and comprises the predetermined number of initial bits before the count value of the counter has reached the predetermined count value; and if a digital representation comprising the predetermined number of initial bits has restarted: determining whether the restarted digital representation has ended and marking, by the latch circuit, that the digital representation has ended; and restarting the counter when the digital representation has been marked as ended; determining whether the restarted digital representation has ended and marking, by the latch circuit, that the digital representation has ended; and restarting the counter when the digital representation has been marked as ended; if a digital representation comprising the predetermined number of initial bits has not restarted before the count value of the counter has reached the predetermined count value, turning off the clock circuit when the predetermined count value has been reached.