SPRUIE9D May 2017 – May 2024 DRA74P , DRA75P , DRA76P , DRA77P
The Sync on List Control descriptor is a mechanism to ensure that multiple lists have all reached a common point. The Sync on List descriptor uses the Source field as a mask for each list that should be synchronized which must include the list where the control descriptor resides. Once all lists specified in the source field have reached their Sync on List descriptor all lists will resume with the lowest list number resuming first. All Sync on List Control descriptors in each of the lists must have the same source field so that all lists will synchronize upon reaching that point.
If it is desired to synchronize list 0 and list 1 then the source field would be 0x3. If it is desired to synchronize list 1, list 3, and list 4 then the source field would be 0x1a. Word 0, Word 1 and Word 2 are reserved.
Bits | Name | Description |
---|---|---|
31:27 | Packet Type | Host Packet Descriptor Type = Ch |
26:24 | Reserved | Reserved |
23:16 | Source | Specifies the source used for the control event. |
15:4 | Reserved | Reserved for future use |
3:0 | Control | Control type = 1h |