5-78
Bus Interface
AMD-K5 Processor Technical Reference Manual
18524C/0—Nov1996
5.2.29
IERR (Internal Error)
Output
Summary
The processor drives IERR only in Functional-Redundancy
Checking mode. If the processor is the checker and it detects a
difference in signal outputs between the master and itself, it
asserts IERR. No other errors are reported with IERR.
Driven
The processor drives IERR every clock while the processor is
operating as the checker in the Functional-Redundancy Check-
ing mode. If an error is detected, IERR is asserted for one
clock, starting two clocks after the detection of the error.
IERR is only driven in Functional-Redundancy Checking mode
when the processor is the checker, including while PRDY is
asserted within this mode.
Details
The processor enters Functional-Redundancy Checking mode
as the checker if FRCMC is asserted at RESET. In this mode,
all of the processor’s output and bidirectional signals (except
IERR and TDO) are floated and tied to those of the master pro-
cessor. Both processors execute the same instructions, and the
checker compares the state of the master’s output and bidirec-
tional signals with the state that the checker itself would have
driven for the same instruction stream.
If a mismatch occurs on such a comparison, the checker asserts
IERR for one clock, two clocks after the detection of the error.
Both the master and the checker continue running the check-
ing program after an error occurs. No action other than the
assertion of IERR is taken by the processor.
No other errors are reported with IERR. Unlike the Pentium
processor, the AMD-K5 processor does not report parity errors
on IERR for every cache or TLB access. Instead, the AMD-K5
processor fully tests cache parity during the built-in self test
(BIST), which is invoked by asserting INIT during RESET.
Summary of Contents for AMD-K5
Page 1: ...AMD K5 Processor Technical Reference Manual TM...
Page 10: ...x AMD K5 Processor Technical Reference Manual 18524C 0 Nov1996...
Page 24: ...1 4 Overview AMD K5 Processor Technical Reference Manual 18524C 0 Nov1996...
Page 54: ...2 30 Internal Architecture AMD K5 Processor Technical Reference Manual 18524C 0 Nov1996...
Page 116: ...4 26 Performance AMD K5 Processor Technical Reference Manual 18524C 0 Nov1996...
Page 356: ...6 44 System Design AMD K5 Processor Technical Reference Manual 18524C 0 Nov1996...
Page 380: ...7 24 Test and Debug AMD K5 Processor Technical Reference Manual 18524C 0 Nov1996...
Page 396: ...A 16 AMD K5 Processor Technical Reference Manual 18524C 0 Nov1996...
Page 406: ...I 10 Index AMD K5 Processor Technical Reference Manual 18524C 0 Nov1996...