Signal Descriptions
5-121
18524C/0—Nov1996
AMD-K5 Processor Technical Reference Manual
5.2.48
SMIACT (System Management Interrupt Active)
Output
Summary
The processor acknowledges the assertion of SMI with the
assertion of SMIACT. The acknowledgment signifies the pro-
cessor’s readiness to enter System Management Mode (SMM)
and begin executing the service routine for that interrupt
mode.
Driven
The processor drives SMIACT from after the later of (a) the
last expected BRDY of any in-progress bus cycle, or (b) the
assertion of EWBE with or following the last expected BRDY,
until the return from the SMM interrupt handler via the RSM
instruction.
SMIACT is driven during memory cycles (including cache
writethroughs and writebacks), cache accesses, I/O cycles,
locked cycles, special bus cycles, and interrupt acknowledge
operations in the normal operating modes (Real, Protected,
and Virtual-8086) and in SMM; in the Shutdown, Halt, or Stop
Grant states; or while AHOLD, BOFF, HLDA, or PRDY is
asserted. SMIACT is not driven in the Stop Clock state, or
while RESET is asserted.
Details
The memory controller normally uses the assertion of SMIACT
to enable SMM memory, so that the first memory access in
SMM is to the base of the state-save area in the SMM memory
space.
The processor remains in SMM, continuing to assert SMIACT,
until it executes the RSM instruction. For more information
regarding SMM, see the description of SMI on page 5-116, Sec-
tion 6.1.4 on page 6-5, and Section 6.3 on page 6-23.
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...