Intel® Quartus® Prime Pro Edition User Guide: Platform Designer
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6.1.10. 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. |