Signal Description
R
2.4.4AGP Strobes Signals
Signal Name | Type | Description |
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AD_STB0 | I/O | Address/Data Bus |
| (s/t/s) | data on AD[15:0] and the C/BE[1:0]# signals. The agent that is providing |
| AGP | the data drives this signal. |
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AD_STB0# | I/O | Address/Data Bus |
| (s/t/s) | provides timing information for the AD[15:0] and C/BE[1:0]# signals. The |
| AGP | agent that is providing the data drives this signal. |
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AD_STB1 | I/O | Address/Data Bus |
| (s/t/s) | clocked data on AD[31:16] and C/BE[3:2]# signals. The agent that is |
| AGP | providing the data drives this signal. |
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AD_STB1# | I/O | Address/Data Bus |
| (s/t/s) | to the AD_STB1 signal. It is used to provide timing for |
| AGP |
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SB_STB | I | Sideband Strobe: This signal provides timing for 2x- and 4x- clocked |
| AGP | data on the SBA[7:0] bus. It is driven by the AGP master after the system |
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| has been configured for 2x- or 4x- clocked sideband address delivery. |
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SB_STB# | I | Sideband Strobe Compliment: SB_STB# is the differential compliment |
| AGP | to the SB_STB signal. It is used to provide timing for |
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2.4.5AGP/PCI Signals
For transactions on the AGP interface carried using AGP FRAME# protocol, these signals operate similar to their semantics in the PCI 2.1 specification the exact role of all AGP FRAME# signals are defined below.
Signal Name | Type | Description |
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G_FRAME# | I/O | FRAME: During FRAME# Operations, G_FRAME# is an output when the |
| s/t/s | MCH acts as an initiator on the AGP Interface. |
| AGP |
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G_IRDY# | I/O | Initiator Ready#: This signal indicates the AGP compliant master is |
| s/t/s | ready to provide all write data for the current transaction. Once G_IRDY# |
| AGP | is asserted for a write operation, the master is not allowed to insert wait |
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| states. The master is never allowed to insert a wait state during the initial |
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| data transfer (32 bytes) of a write transaction. However, it may insert wait |
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| states after each |
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G_TRDY# | I/O | Target Ready: This signal indicates the AGP compliant target is ready to |
| s/t/s | provide read data for the entire transaction (when the transfer size is less |
| AGP | than or equal to 32 bytes) or is ready to transfer the initial or subsequent |
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| block (32 bytes) of data when the transfer size is greater than 32 bytes. |
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| The target is allowed to insert wait states after each block (32 bytes) is |
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| transferred on write transactions. |
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G_STOP# | I/O | STOP: G_STOP Is an input when the MCH acts as a |
| s/t/s | AGP initiator and an output when the MCH acts as a |
| AGP | AGP target. G_STOP# is used for disconnect, retry, and abort |
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| sequences on the AGP interface. |
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26 | Intel® 82845 MCH for SDR Datasheet |