1) The FS2221 provides an electrical and mechanical interface from
the AGP connector to Agilent logic analyzers for passive bus analysis.
2) The FS2221 provides software to set up the Agilent logic analyzer
and to allow powerful state analysis in real time of the AGP transactions.
With the FS2221, designers can use their Agilent logic analyzer
as a passive AGP 4X analyzer. The FuturePlus Transaction Inverse
Assembler, coupled with the advanced triggering and system performance
software of Agilent's logic analyzers, give the user a powerful tool
in debugging, testing, and verifying compliance of PC's and workstations
incorporating the AGP4X in the graphics system.
The FS2221 probe board plugs into an AGP4X socket. Four coax cables
attach the probe board to the FS2221, with three cables carrying
the 4X signals and one cable carrying the 1X signals. Specially
selected series resistors are used to isolate the probe from the AGP.
Since the AGP is a series-terminated bus, it is essential that designers
keep the end-to-end AGP channel length less than 6" to insure
proper capture of all transactions.
Please Note: The FS2221 does not support the AGP Pro version.
Using the FS2221 in this environment will cause damage to the
probing system.
With the AGP4X transferring data at 266 MHz, the minimum setup and
hold time is 1.1 ns. Since the AGP4X is series terminated, data
is monitored at the receivers. The FS2221 is a conventional "interposer" design
that plugs into the AGP connector in series with the AGP graphics
card. The FS2221 can monitor the AGP in all three modes of operation,
1X, 2X and 4X. The AGP has 32 bits of Address/Data, 4 bits of Command/Byte
Enables, 8 bits of sideband data, and 15 bits of control (1X clock).
The strobed signals are valid on both edges. The strobe frequency
is 133 MHz in 4X mode, and 66 MHz in 2X/1X mode. The 1X clock frequency
is 66 MHz.
Important Design Considerations
Due to the complexity of the AGP technology, we recommend that
the motherboard trace length be as short as possible and that the
probe be placed in the near center of the overall trace length.
This overall trace length includes the motherboard, the interposer
board of the FS2221 (0.8 inches) and the AGP add-in card. In the environment
that the probe was qualified (Intel CRB) the motherboard trace
length was 2.5 inches and a AGP card length was 1.5 inches. This gives
an end-to-end trace length of 4.8" (2.5+0.8+1.5) The probe was offset
0.5" from the center. We recommend that all customers qualify the
probe in the targeted environment. This can be done by creating
a robust test of repeatable data patterns transfered at 2X and
4X and then using the logic analyzer compare tool to verify that
the data is captured by the probe correctly. The test should be
run several times and the data should compare correctly every time.
We cannot test all the different platforms that the probe is being
used in, thus we recommend this qualification process. Please click
here to see a AGP4X Probe Timing Graph that will be of assistance
to you. Questions concerning this process should be directed to
FuturePlus Technical Support.
AGP
4X Analysis Probe Mechanical Drawing
AGP
4X Probing System Drawing
