Interphase Tech 4221 Command Response Status Word (CRSW)

Chapter 3 - MACSI Host Interface

Command Response Block (CRB)

The CRB is used by the controller to post completed commands back to the host. It consists of the following fields:

Table 3-8. Command Response Block

Command Response Block

Addr	15	14	13	12	11	10	9		8	7	6	5	4	3	2	1	0
0x730					Command Response Status Word (CRSW)
0x732								Reserved
0x734							Command Tag
0x736								(4 Bytes)
0x738			Reserved									Work queue number
0x73A								Reserved
to								(8 Bytes)
0x73E

Command Response Status Word (CRSW)

The CRSW describes the nature of the response, and includes a handshake bit similar to the CQE Go bit to synchronize the controller and the host.

Table 3-9. Command Response Block

Command Response Block

Addr	15	14	13	12	11	10	9	8	7	6	5	4	3	2	1	0
0x730									MC		QMS	CE	EX	ER	CC	CRBV

Command Response Block Valid (CRBV)

The controller sets this bit after assembling the returned commands in host accessible memory. If Offboard postbacks are enabled, the returned commands will be located in both the onboard memory and the offboard memory. If commands are being returned one at a time (single completion), the entire IOPB will be located in the Returned IOPB space. If multiple commands are being returned, several Multiple Command return structures will located in Short I/O, starting at the same location as used for the returned IOPB.

Command Complete (CC)

This bit is set when an IOPB is being returned. If this bit is set, a returned IOPB will be located in Short I/O.

62