82596DX Datasheet, PDF (52/77 Pages) Intel Corporation – HIGH-PERFORMANCE 32-BIT LOCAL AREA NETWORK COPROCESSOR

82596DX SX
DIAGNOSE
The Diagnose Command triggers an internal self-test procedure that checks internal 82596 hardware which
includes
 Exponential Backoff Random Number Generator (Linear Feedback Shift Register)
 Exponential Backoff Timeout Counter
 Slot Time Period Counter
 Collision Number Counter
 Exponential Backoff Shift Register
 Exponential Backoff Mask Logic
 Timer Trigger Logic
This procedure checks the operation of the Backoff block which resides in the serial side and is not easily
controlled The Diagnose command is performed in two phases
The format of the 82596 Diagnose command is
82586 and 32-Bit Segmented Modes
31
ODD WORD
16 15
EVEN WORD
0
EL S I X X X X X X X X X X 1 1 1 C B OK 0 F 0 0 0 0 0 0 0 0 0 0 0
X X X X X X X X X X X X X X X X A15
LINK OFFSET
A0
Linear Mode
31
ODD WORD
16 15
EVEN WORD
0
EL S I 0 0 0 0 0 0 0 0 0 0 1 1 1 C B OK 0 F 0 0 0 0 0 0 0 0 0 0 0
A31
LINK ADDRESS
A0
Figure 36 Diagnose
where
LINK ADDRESS
EL B C I S
Bits 19–28
CMD (bits 16–18)
OK (bit 13)
F (bit 11)
As per standard Command Block (see the NOP command for details)
Reserved (0 in the 32-bit Segmented and Linear Modes)
The Diagnose command Value 7h
Indicates error free completion
Indicates that the self-test procedure has failed
RECEIVE FRAME DESCRIPTOR
Each received frame is described by one Receive Frame Descriptor (see Figure 37) Two new memory
structures are available for the received frames The structures are available only in the Linear and 32-bit
Segmented modes
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