Visible to Intel only — GUID: iyg1522788136447
Ixiasoft
Visible to Intel only — GUID: iyg1522788136447
Ixiasoft
5.1.10. Waitrequest Allowance Adapter
The Waitrequest Allowance adapter provides the following features:
- The adapter is used in the memory-mapped domain and operates with signals on the memory-mapped interface.
- Signal widths and all properties other than waitrequestAllowance are identical on host and agent interfaces.
- The adapter does not modify any command properties such as data width, burst type, or burst count.
- The adapter is inserted by the Platform Designer interconnect software when a host and agent with different waitrequestAllowance property are connected.
When the agent has a waitrequestAllowance = n the host must deassert read or write signals after <n> transfers when waitrequest is asserted.
Host (m) / Agent (n) waitrequestAllowance | Adaptation Required | Description | Adapter Function |
---|---|---|---|
m = n | No | The host waitrequestAllowance is equal to the agent's waitrequestAllowance. |
All signals are passed through. |
m = 0; n > 0 | Yes | The host cannot send when waitrequest=1, but holds the value on the bus. This would result in the agent receiving multiple copies. Requires adaptation to prevent. |
The adapter deasserts valid when input waitrequest is asserted. |
m < n; m != 0 | No | The host can send <m> transfers after waitrequest is asserted. The agent receives fewer than <n> transfers, which is acceptable. |
All signals are passed through. |
m > n; n = 0 | Yes | The agent cannot accept transfers when waitrequest is asserted. Transfers sent when waitrequest=1 can be lost. Prevention requires adaptation in the form of transfer buffering. |
If the input waitrequest is asserted, the adapter buffers the input data. |
m > n; n > 0 | Yes | The agent cannot accept more than <n> transfers after waitrequest is asserted, however the host can send up to <m> transfers. Transfers ( <m> – <n>) can be lost. Prevention requires adaptation in the form of transfer buffering. |
The adapter buffers the input data. |