Technical Reference Guide
on the rising edge of AD_STBx. The signal level for
GP 2X transfers may be 3.3 or 1.5 VDC.
igure 4-6. AGP 2X Data Transfer (Peak Transfer Rate: 532 MB/s)
he rising edge of AD_STBx. The signal level for
GP 2X transfers may be 3.3 or 1.5 VDC.
igure 4-6. AGP 2X Data Transfer (Peak Transfer Rate: 532 MB/s)
in
shown in Figure 4-7, 4-byte
lock DnA is latched by the falling edge of AD_STBx while DnB is latched by the falling edge of
Figure 4-7. AGP 4X Data Transfer (Peak Transfer Rate: 1064 MB/s)
in
shown in Figure 4-7, 4-byte
lock DnA is latched by the falling edge of AD_STBx while DnB is latched by the falling edge of
Figure 4-7. AGP 4X Data Transfer (Peak Transfer Rate: 1064 MB/s)
AGP 2X Transfers
(NOT SUPPORTED IN THESE SYSTEMS)
During AGP 2X transfers, clocking is basically the same as in 1X transfers except that the 66-
MHz CLK signal is used to qualify only the control signals. The data bytes are latched by an
additional strobe (AD_STBx) signal so that an 8-byte transfer occurs in one CLK cycle (Figure 4-
6). The first four bytes (DnA) are latched by the receiving agent on the falling edge of AD_STBx
and the second four bytes (DnB) are latched
AA
T1 T2 T3 T4 T5 T6 T7
TRDY-
GNT-
CLK
AD_STBx
AD
D1A D2A D3A
D1B D2B D3B D4A D4B
ST0..2
00x
xxx
xxx
xxx
xxx
xxx
FF
AGP 4X Transfers
The AGP 4X transfer rate allows sixteen bytes of data to be transferred in one clock cycle. As
2X transfers the 66-MHz CLK signal is used only for qualifying control signals while strobe
signals are used to latch each 4-byte transfer on the AD lines. As
AGP 4X Transfers
The AGP 4X transfer rate allows sixteen bytes of data to be transferred in one clock cycle. As
2X transfers the 66-MHz CLK signal is used only for qualifying control signals while strobe
signals are used to latch each 4-byte transfer on the AD lines. As
bb
AAD_STBx-. The signal l l for AGP 4X transfers is 1.5 VDC. D_STBx-. The signal l l for AGP 4X transfers is 1.5 VDC.
T1 T2 T3
T4
D1A D2A D3A D1B D2B D3B D4A D4B
AD
eveeve
CLK
AD
AD_STBx
_STBx-
00x xxx xxx xxx
ST0..2
hp compaq d330 and d530 Series of Personal Computers
Featuring the Intel Pentium 4 Processor
First Edition - June 2003
4-11
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