Device is Asleep

When the device is asleep, it ignores all but the Wake condition.

Wake - Upon the rising edge of SDA, after SDA has been held low for a period ≥ t_WLO, the device exits the Low-Power mode. After a delay of t_WHI, it will be ready to receive I²C commands.
The device ignores any levels or transitions on the SCL pin when the device is idle or asleep and during t_WLO. At some point during t_WHI, the SCL pin is enabled and the conditions listed in Section Device is Awake are honored.

The Wake condition requires that either the system processor manually drives the SDA pin low for t_WLO, or a data byte of 0x00 be transmitted at a clock rate sufficiently slow so that SDA is low for a minimum period of t_WLO. When the device is awake, the normal processor I²C hardware and/or software can be used for device communications. This includes the I/O sequences required to put the device back into Low-Power (i.e., Sleep) mode.

Tip: A simple way to generate a wake pulse is to send a byte of 0x00 at 100 kHz. Subsequent commands can be run at a higher frequency.

In the I²C mode, the device will ignore a wake sequence that is sent when the device is already awake.

Multiple Devices on the Bus

When there are multiple devices on the bus and the I²C interface is run at speeds of less than ~300 kHz¹, the transmission of certain data patterns will cause the ATECC608A-TNGTLS devices on the bus to wake up. The lower the frequency the higher the probability that the device wakes up. Because subsequent device addresses transmitted along the bus only match the desired devices, the ATECC608A-TNGTLS will not respond but will be awake. It is recommended that after communicating with another device at slow frequencies, a sleep or idle sequence be issued to place the ATECC608A-TNGTLS back into a known state.

Important: t_WLO is the minimum time that the system must provide to ensure that the ATECC608A-TNGTLS will wake under all manufacturing and environmental conditions. In actuality, the device may wake up with a lesser pulse width.