Datasheet

TSB81BA3E
www.ti.com SLLS783A –MAY 2009–REVISED MAY 2010
Table 25. Request Type Encoding (continued)
LR1-LR4 NAME DESCRIPTION
Current request. The PHY arbitrates for the bus to send an asynchronous packet in the current
0100 Current
fairness interval.
0101 Reserved Reserved
Isochronous even request. The PHY arbitrates for the bus to send an isochronous packet in the even
0110 Isoch_Req_Even
isochronous period.
Isochronous odd request. The PHY arbitrates for the bus to send an isochronous packet in the odd
0111 Isoch_Req_Odd
isochronous period.
1000 Cyc_Start_Req Cycle start request. The PHY arbitrates for the bus to send a cycle start packet.
1001 Reserved Reserved
1010 Reg_Read Register read request. The PHY returns the specified register contents through a status transfer.
1011 Reg_Write Register write request. Write to the specified register in the PHY.
Isochronous phase even notification. The link reports to the PHY that:
1100 Isoch_Phase_Even 1) A cycle start packet has been received.
2) The link has set the isochronous phase to even.
Isochronous phase odd notification. The link reports to the PHY that:
1101 Isoch_Phase_Odd 1) A cycle start packet has been received.
2) The link has set the isochronous phase to odd.
1110 Cycle_Start_Due Cycle start due notification. The link reports to the PHY that a cycle start packet is due for reception.
1111 Reserved Reserved
For a bus request, the length of the LREQ bit stream is 11 bits as shown in Table 26.
Table 26. Bus Request
BIT(s) NAME DESCRIPTION
0 Start bit Indicates the beginning of the transfer (always 1)
1–4 Request type Indicates the type of bus request (See Table 25)
5 Request format Indicates the packet format to be used for packet transmission (See Table 27)
Indicates the speed at which the link sends the data to the PHY (See Table 28 for the encoding of this
6–9 Request speed
field)
10 Stop bit Indicates the end of the transfer (always 0). If bit 6 is 0, then this bit can be omitted.
Table 27 shows the 1-bit request format field used in bus requests.
Table 27. Bus Request Format Encoding
LR5 DATA RATE
0 Link does not request either Beta or legacy packet format for bus transmission
1 Link requests Beta packet format for bus transmission
Table 28 shows the 4-bit request speed field used in bus requests.
Table 28. TBus Request Speed Encoding
LR6-LR9 DATA RATE
0000 S100
0001 Reserved
0010 S200
0011 Reserved
0100 S400
0101 Reserved
0110 S800
All Others Invalid
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