SECTION 5
PCI 9080
PIN DESCRIPTION
PLX Technology, Inc., 1997
Page 98
Version 1.02
5.5 S BUS MODE PIN OUT
Table 5-8. S Bus Mode Interface Pin Description
S Bus Mode
Symbol
Signal Name
Total
Pins
Pin
Type
Pin
Number
Function
ALE
Address Latch
Enable
1
O
TS
8 mA
161
Asserted during the address phase and negated before the data
phase.
AS#
Address Strobe
1
I/O
TS
12 mA
154
Indicates valid address and the start of a new bus access. Asserted
for the first clock of a bus access.
BLAST#
Burst Last
1
I/O
TS
8 mA
155
Signal driven by the current local bus master to indicate the last
transfer in a bus access.
BTERM#
Burst Terminate
1
I
146
For processors that burst up to eight words and do not use BTERM#
input. If Bterm is disabled through the PCI 9080 configuration
registers, PCI 9080 also bursts up to eight words. If enabled, PCI
9080 continues to burst until a BTERM# input is asserted. BTERM#
breaks up a burst cycle and causes another address cycle to occur.
Used in conjunction with the PCI 9080 programmable wait state
generator.
DEN#
Data Enable
1
O
TS
12 mA
145
Used in conjunction with DT/R# to provide control for data
transceivers attached to the local bus.
DT/R#
Data
Transmit/Receive
1
O
TS
12 mA
138
Used in conjunction with DEN# to provide control for data transceivers
attached to the local bus. When asserted, the signal indicates the PCI
9080 is receiving data.
LA[31:16]
Address Bus
16
I/O
TS
8 mA
136, 135,
133-125,
122-118
Carries the upper 16 bits of the address.
LABS[3:1]
Address Bus Burst
3
I/O
TS
8 mA
162-164
Carries the word address of the 32 bit memory address. These bits
are incremented during a burst access.
LAD[15:1],D0
Address/Data Bus
16
I/O
TS
8 mA
117-115,
113-106,
103-99
During the address phase, carries the lower physical address bits.
During the data phase, carries 16 bits of data.
LBE[1:0]#
Byte Enables
2
I/O
TS
12 mA
141,142
Indicate which of the two bytes are active during a data cycle.
LCLK
Local Clock
1
I
160
Local clock input.
Note:
processor’s RESET# input must be connected to PCI 9080
LRESETo# output. This enables PCI 9080 to determine the phase of
the 2x clock processor.
For i960
S processor systems, CLK2 input. i960
S
LHOLD
Hold Request
1
O
TP
8 mA
158
Asserted to request use of the local bus. The local bus arbiter asserts
LHOLDA when control is granted.
LHOLDA
Hold Acknowledge
1
I
159
Asserted by the local bus arbiter when control is granted in response
to LHOLD. The bus should not be granted to the PCI 9080 unless
requested by LHOLD.