Figure 32-31 shows all messages exchanges between power-on event up to when the platform is ready. The sequencing aims to depict the complete sequence without any specific connecting issues that may appear.
The following time phases can be identified during booting from SATA interface:
- T0: the SATA_PHY is powered and device reset is maintained until all Power-management IC companion powers are set.
- T1: the ROM code validates a SATA SSD device detection.
- Within the T1-T2 time interval: the SATA host issues a COMRESET sequence for a minimum of 6 bursts (and a multiple of 6) to force a hardware reset to the SATA peripheral device.
- T2: As long as the attached SATA SSD device does not explicit reset request (COMINIT), the host issues COMRESET sequences
- Within the T2-T3 time interval, once the host release the COMRESET sequence (made of 6 bursts minimum), the device responds with a COMINIT to request a communication initialization (It requests a reset from the host).
- Within the T3-T4 time interval, the SATA host controller may calibrate at T3, but issues a COMWAKE sequence to the peripheral in order to inform the other part the wish to use the link.
- Within the T4-T5 time interval, the SSD device responds and may calibrate. The device response is made of 6 burst COMWAKE sequence.
- Within the T5-T6 time interval, SATA host controller shall start transmitting D10.2 characters no later than a defined moment.
- Within the T6-T7 time interval, when the device host detects the COMWAKE from the device, it starts transmitting D10.2 character at its lowest speed.
- At the same time within T5-T7 time interval, continuous stream of device ALIGN sequence (following the 6 bursts COMWAKE sequence) starting at the device highest speed.
- T7: Without any SATA host’s answer (D10.2 character), the device ALIGN sequence is repeated for as many slower speeds as are supported. When host receives ALIGN sequence, it locks.
- in case no proposed speeds are supported by the host, the device enters in error state.
- in case no ALIGNp sequence is received by the host within a defined time gap after detecting the release of the device COMWAKE, the host restarts the power on sequence indefinitely until stop by user intervention.
- Within the T7-T8 time interval, as soon as the device SATA host locks, it issues an ALIGN sequence to the attached SATA SSD device that also locks
- Within the T8-T9 time interval, the SATA peripheral device sends a SYNC primitive to inform the communication link is established.
- Within the T9-T10 time interval, once the link has been set successfully, the boot loader is transferred from the SATA peripheral device to device internal on-chip RAM
After passing through all above described phases, the device is ready to load OS source from SSD to the device DDR RAM.