Fujitsu MBA3147RC, MBC2036RC, MBC2073RC, MBA3300RC, MBA3073RC SSP frame interlock requirements

SAS Interface

Table 1.31 SSP frame interlock requirements

SSP frame type	Interlock requirement
COMMAND	Interlocked
TASK	Interlocked
XFER_RDY	Interlocked
DATA	Non-interlocked
RESPONSE	Interlocked

Before transmitting an interlocked frame, an SSP phy shall wait for all SSP frames to be acknowledged with ACK or NAK, even if credit is available. After transmitting an interlocked frame, an SSP phy shall not transmit another SSP frame until it has been acknowledged with ACK or NAK, even if credit is available.

Before sending a non-interlocked frame, an SSP phy must wait for the following frames to be acknowledged with ACK or NAK, even if credit is available:

a)all non-interlocked frames with different tags; and

b)all interlocked frames;

After sending a non-interlocked frame, an SSP phy may send another non- interlocked frame with the same tag if credit is available. The SSP phy must not send the following frames until all SSP frames have been acknowledged with ACK or NAK, even if credit is available:

a)a non-interlocked frame with a different tag; or

b)an interlocked frame;

Interlocking does not prevent sending and receiving interlocked frames simultaneously (e.g., an SSP INIT phy can send a COMMAND frame while receiving XFER_RDY, DATA, or RESPONSE frames for a different command).

An SSP phy may transmit primitives responding to traffic it is receiving (e.g., an ACK or NAK to acknowledge an SSP frame, an RRDY to grant more receive credit, or a CREDIT_BLOCKED to specify that no more RRDYs are going to be transmitted in the connection) while waiting for an interlocked frame it transmitted to be acknowledged. These primitives may also be interspersed within an SSP frame.

74 C141-C013