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Important: The information in this document is obsolete and should not be used for new development.

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Inside Macintosh: Devices /
Chapter 3 - SCSI Manager / SCSI Manager Reference
SCSI Manager Routines /


SCSIStat

You can use the SCSIStat function to obtain status information from the SCSI Manager.

FUNCTION SCSIStat: Integer;
DESCRIPTION
The SCSIStat function returns a 16-bit value containing status information. This information includes the state of all SCSI bus control signals as well as the status of the NCR 5380 SCSI controller chip (or equivalent hardware). In Macintosh models that use other SCSI controller hardware, the status information conforms to the 5380 format, but may not represent the actual state of the hardware.

IMPORTANT
Because hardware differences make it difficult to accurately interpret the status information, use of this function is not recommended.
Bits 0 through 9 represent the state of the SCSI bus signals, and bits 10 through 15 report status information from the SCSI controller hardware. The status bits have these meanings:
BitNameMeaning
0DBPData parity signal
1/SELSelect signal
2/I/OI/O signal
3/C/DCommand/Data signal
4/MSGMessage signal
X/REQRequest signal
6/BSYBusy signal
7/RSTReset signal
8/ACKAcknowledge signal
9/ATNAttention signal
10BSY ERRBusy error
11PHS MATPhase match
12INT REQInterrupt request
13PTY ERRParity error
14DMA REQDirect memory access request
15END DMADirect memory access complete

Note
The SCSI bus control signals are active low; therefore, the status bits represent the complement of the bus signals.
ASSEMBLY-LANGUAGE INFORMATION
The trap macro and routine selector for SCSIStat are
Trap macroSelector
_SCSIDispatch$000A

RESULT CODES
noErr0No error
scCommErr2Communications error, operation timeout
scPhaseErrXPhase error on the SCSI bus
SEE ALSO
See "SCSI Bus Signals," beginning on page 3-4, for an overview of SCSI bus signals. Refer to the SCSI specification for detailed information about SCSI bus signals. Refer to the NCR 5380 SCSI controller specification for information about that device.


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© Apple Computer, Inc.
3 JUL 1996