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Figure 6 : cominit sequence
Description:
1.Host/device are powered and operating normally with some form of active communication.
2.Some condition in the device causes the device to issues a COMINIT
3.Host calibrates and issues a COMWAKE.
4.Device responds – The device detects the COMWAKE sequence on its RX pair and calibrates its transmitter (optional). Following calibration the device sends a six burst COMWAKE sequence and then sends a continuous stream of the ALIGN sequence starting at the device's highest supported speed. After ALIGNP Dwords have been sent for 54.6 us (2048 nominal Gen1 Dword times) without a response from the host as determined by detection of ALIGNP primitives received from the host, the device assumes that the host cannot communicate at that speed. If additional speeds are available the
device tries the next lower supported speed by sending ALIGNP Dwords at that rate for 54.6 us (2048 nominal Gen1 Dword times.) This step is repeated for as many slower speeds as are supported. Once the lowest speed has been reached without response from the host, the device enters an error state.
5.Host locks – after detecting the COMWAKE, the host starts transmitting D10.2 characters at its lowest supported rate. Meanwhile, the host receiver locks to the ALIGN sequence and, when ready, returns the ALIGN sequence to the device at the same speed as received. A host shall be designed such that it acquires lock in 54.6 us (2048 nominal Gen1 Dword
Transcend Information Inc.
10 | V1.2 |
