4.2 Clock (SCL/CLK)

In the asynchronous T=0 protocol, the SCL/CLK input is used to provide the device with a carrier frequency f. The nominal length of one bit emitted on I/O is defined as an "Elementary Time Unit" (ETU) and is equal to 372/f. When the synchronous protocol is used, the SCL/CLK input is used to clock data in on the positive clock edge and clock data out on the negative clock edge.