Accelerated Graphics Port Interface Specification

AGP3.0 Interface Specification
Rev. 1.0
76
Table 37: AGP Master Signal State During and After RESET
Signal Name AGP3.0 Signaling Signal Name AGP 2.0 Signaling
AGP3.0 During Reset After Reset
1
AGP2.0 During Reset After Reset
1
REQ Float Drive Low REQ# Float Drive High
GNT Float Term GNT# Float (input) Float (input)
ST[2:0] Float Term ST[2:0] Float (input) Float (input)
DEVSEL Float Term DEVSEL# Float Float
AD[31:0]
C#/BE[3:0]
PAR
Float Term AD[31:0]
C/BE[3:0]#
PAR
Float Float
DBI_LO Float Term (Not used)
Float (not used)
Float (not used)
ADSTBF[1:0]
ADSTBS[1:0]
Float Term ADSTB[1:0]
ADSTB[1:0]#
Float Float
DBI_HI Float Term PIPE# Float Float or Drive High
SBA[7:0] Float Drive Low SBA[7:0]# Float Float or Drive High
(Note 2)
SB_STBF
SB_STBS
Float Drive Low SB_STB
SB_STB#
Float Float or Drive High
Float or Drive Low
(Note 2)
FRAME
IRDY
TRDY
STOP
Float Term FRAME#
IRDY#
TRDY#
STOP#
Float Float
RBF
WBF
Float Drive Low
(Note 2)
RBF#
WBF#
Float
Float or Drive High
(Note 2)
PERR
SERR
Float Term PERR#
SERR#
Float Float
/ NOTE
1. The values under “After Reset” apply to the idle cycles that follow RESET.
2. The sideband signals are optional for AGP2.0 master devices and RBF and WBF are optional
for all AGP masters.
3. Drive Low = Driven to AGP3.0 low value, which may be the same as the Termination.
4. Drive High = Driven to AGP2.0 high value.
5. Term = Termination impedance to ground. This is the standard AGP3.0 termination. A
default value must be used prior to the impedance of the terminator being calibrated to
guarantee a low logic level.