During an I2C write packet, the ECC608-TNGHNT interprets the second byte sent as the word address, which indicates the packet function as it is described in the table below:
| Name | Value | Description |
|---|---|---|
| Reset | 0x00 | Resets the address counter. The next I2C read or write transaction will start with the beginning of the I/O buffer. |
| Sleep (Low-power) | 0x01 | The ECC608-TNGHNT goes into the low-power Sleep mode and ignores all subsequent I/O transitions until the next Wake flag. The entire volatile state of the device is reset. |
| Idle | 0x02 | The ECC608-TNGHNT goes into Idle mode and ignores all subsequent I/O transitions until the next Wake flag. The contents of TempKey, MessageDigestBuffer and Alternate Key registers are retained. |
| Command | 0x03 | Writes subsequent bytes to sequential addresses in the input command buffer that follow previous writes. This is the normal operation. |
| Reserved | 0x04 – 0xFF | These addresses must not be sent to the device. |