Intel® Quartus® Prime Standard Edition User Guide: Partial Reconfiguration

ID 683499
Date 9/24/2018
Document Table of Contents

1.3.2. AND/OR Mode

The AND/OR mode refers to how the bits are rewritten. Partial reconfiguration with AND/OR uses a two-pass method.

Simplistically, this can be compared to bits being ANDed with a MASK, and ORed with new values, allowing multiple PR regions to vertically overlap a single column. In the first pass, all the bits in the CRAM frame for a column passing through a PR region are ANDed with '0's while those outside the PR region are ANDed with '1's. After the first pass, all the CRAM bits corresponding to the PR region are reset without modifying the static region. In the second pass for each CRAM frame, new data is ORed with the current value of 0 inside the PR region, and in the static region, the bits are ORed with '0's so they remain unchanged. The programming file size of a PR region using the AND/OR mode could be twice the programming file size of the same PR region using SCRUB mode.

Figure 5. AND/OR ModeThis is the floorplan of a FPGA using AND/OR mode, with two PR regions, with columns that overlap.
Note: If you have overlapping PR regions in your design, you must use AND/OR mode to program all PR regions, including PR regions with no overlap. The Intel® Quartus® Prime software will not permit the use of SCRUB mode when there are overlapping regions. If none of your regions overlap, you can use AND/OR, SCRUB, or a mixture of both.

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