Interphase Tech CONDOR 4221 User Manual download pdf (Page 75)

Command Response Block (CRB)

Error (ER)

This bit is set with Command Complete when a returned IOPB completed with an error. Errored commands

are never returned via the Multiple Completion mechanism. The nature of the error can be determined by

examining the Return Status field in the returned IOPB.

Exception (EX)

This bit is set with Command Complete to indicate that the command completed with some kind of exception,

which can be determined by examining the Return Status field in the returned IOPB.

Controller Error (CE)

This bit is set when a controller error is being returned. The controller error vector and level specified in the

Initialize Controller IOPB will be used to generate the interrupt. The error code will be returned at offset

0x740 from the base of short I/O. The only error code currently supported is 0xff, Controller Panic, which

will also include an ASCII string containing the file name and line number generating the panic, beginning at

location 0x744 in short I/O. This string will be null terminated. The only recovery from a controller panic is

to reset and re-initialize the controller. Panic’s should not occur after initial system qualification.

Queue Mode Started (QMS)

This bit is set by the controller when the host sets the Start Queue Mode bit in the Master Control Register.

Immediately the controller will acknowledge the setting of the SQM bit by generating a Command Complete

interrupt, using the interrupt vectors and level specified in the Controller Initialization Block. Subsequently,

all returned commands will have the QMS bit set.

Multiple Completion (MC)

The controller sets this bit when returning multiple completions with a single interrupt. When this bit is set,

there is no returned IOPB in short I/O, but a list of IOPB completion structures instead. The number of

commands being completed is located in the IOPB length field.

Command Tag

For a single completed command interrupt, this field contains the host-assigned Command Tag located in the

Command Queue entry. It is not modified in any way by the controller.

For multiple completed commands, this field is cleared to zero. The command tags of the completed commands are

written instead to a list of completed commands, using the Multiple Completed Returned IOPB structure, defined in

the next section.

IOPB Length

For a single completed command interrupt, this field is undefined.

For multiple completed commands, this field contains the number of commands being returned.

Work Queue Number

For a single completed command interrupt, this field contains the host provided work-queue number specified in the

Command Queue entry.

For multiple completed commands, this controller clears this field to zero.

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Interphase Tech CONDOR 4221 User Manual Page 75