5-42
Bus Interface
AMD-K5 Processor Technical Reference Manual
18524C/0—Nov1996
The processor samples BRDY during all types of bus cycles,
including the following:
■
Single-transfer reads
■
Single-transfer writes (including cache writethroughs)
■
Burst reads (cache line fills)
■
Burst writebacks
■
Special bus cycles
■
Interrupt acknowledge cycles
The number of BRDYs expected by the processor depends on
the type of bus cycle, as follows:
■
One BRDY for an aligned single-transfer cycle, a special
bus cycle, or each of two cycles in an interrupt acknowledge
operation. Additional BRDYs are needed for misaligned
cycles.
■
Four BRDYs, one for each data transfer in a burst cycle.
BRDY may be held asserted throughout the four transfers
of the burst.
All data transfers that are not performed as bursts are per-
formed as one or more single-transfer cycles. For write cycles,
EWBE must be asserted either with or after BRDY in order for
any further writes or certain other operations to be performed
(see the description of EWBE on page 5-62). If system logic
returns more BRDYs than the processor expects for a single-
transfer cycle or a burst cycle, the processor ignores them.
The processor samples the following inputs in the clock in
which system logic asserts BRDY:
■
D63–D0—Every BRDY, for all bus cycles.
■
DP7–DP0—Every BRDY, for all bus cycles.
■
BUSCHK—Every BRDY, for all bus cycles.
■
EWBE—Every BRDY, for write cycles.
■
KEN—First BRDY or NA, whichever occurs first, for read
cycles.
■
PEN—Every BRDY for read cycles, and second BRDY of
interrupt acknowledge operations.
■
WB/WT—First BRDY or NA, whichever occurs first, for
read and write cycles.
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...