1.6.1. Interface with the PR Control Block through a PR Host
- If the PR IP core is instantiated inside the FPGA being reconfigured, it is termed PR with an internal host; the Altera PR IP core helps you perform the transfer of the PR bitstream.
- When the PR IP is instantiated outside the FPGA being reconfigured, it is termed as PR with an external host.
There is a well-defined interface and a specific protocol to transfer the PR bitstream from the external bitstream source to the PR control block. When you use the Altera PR IP core, the protocol requirements are automatically met by the IP.
It is also possible to write your own control logic, or use a Nios® processor to do this PR bitstream transfer. Note that when create your own control logic for the PR Host, you must make sure to meet the interface requirements described later in this chapter.
The figure shows how these blocks should be connected to the PR control block (CB). In your system, you will have either the External Host or the Internal Host, but not both. The external host can be implemented by instantiating the PR IP core outside the FPGA being reconfigured, may be in another Altera FPGA, or processor/PC (PR over PCIe) , or can be implemented by user logic.
The PR mode is independent of the full chip programming mode. You can use any of the supported full chip configuration modes for configuring the full FPGA for your PR design.
If you are creating your own custom logic for implementing a PR internal host, you can use any interface to load the PR bitstream data to the FPGA; for example, from a serial or a parallel flash device; and then format the PR bitstream data to match the FPPx16 interface on the PR Control Block.
When using an external host, you must implement the control logic for managing system aspects of partial reconfiguration on an external device. To use the external host for your design, turn on the Enable PR Pins option in the Device and Pin Options dialog box in the Intel® Quartus® Prime software when you compile your design. If this setting is turned off, then you must use an internal host. Also, you must tie the corectl port on the PR control block instance in the top-level of the design to the appropriate level for the selected mode.