5-4
Bus Interface
AMD-K5 Processor Technical Reference Manual
18524C/0—Nov1996
5.1.1
Signal Characteristics
Table 5-1. Summary of Signal Characteristics
Signal
Type
Sampled (Input) or
Asserted (Output)
2
Internal
Resistor
Floated
3
A20M
1
I
Every clock.
A31–A3
I/O
Output:
From ADS until last expected BRDY of the bus
cycle.
Input:
Same clock as EADS. A4–A3 are disabled for input.
AHOLD +1,
BOFF +1 or
HLDA
ADS
O
First clock of bus cycle.
BOFF +1 or
HLDA
ADSC
O
First clock of bus cycle.
BOFF +1 or
HLDA
AHOLD
I
Every clock.
AP
I/O
(same as A31–A3)
AHOLD +1,
BOFF +1 or
HLDA
APCHK
O
Two clocks after EADS, for one clock.
BE7–BE0
O
From ADS until the last expected BRDY of the bus cycle.
BOFF +1 or
HLDA
BF (BF1–BF0)
I
Falling edge of RESET.
pullup
BOFF
I
Every clock.
BRDY
I
Every clock, from one clock after ADS until the last
expected BRDY of the bus cycle.
BRDYC
I
(same as
BRDY
)
pullup
BREQ
O
First clock of every bus cycle (same as ADS), cache store,
cache-tag recovery, and aliased cache load. Asserted con-
tinuously while processor is held off bus and needs
access to continue.
BUSCHK
I
Every BRDY. Recognized at the next instruction boundary.
pullup
CACHE
O
From ADS until the last expected BRDY of the bus cycle.
Driven for all reads; only driven for writes during write-
backs.
BOFF +1 or
HLDA
CLK
I
Always.
Notes:
1. Can be driven asynchronously or synchronously.
2. The term clock means bus clock (CLK). “+n” means n CLKs later.
3. “+n” means n CLKs after the named signal is sampled active. All outputs and bidirectionals are floated during the float test (FLUSH
at 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...