• MStream_2_3

M-Stream 2.3

* MStream_ChangeLog

M-Stream data has packet structure. Large packets may be split to fragments with same Packet ID to fit in encapsulating frame.

M-Stream 2.0 defines M-Stream Header, Event Header and User Payload data objects. In fragmentation process, M-Stream Header is persistent and should be present in all fragments. Event Header should be present in first fragment only.

Fragment length is defined as number of bytes starting at offset 8. For M-Stream frame of size N 32-bit words, fragment length value is 4*(N-2).

Fragment offset code is number of 64-byte blocks. Fragmentation is performed at 64-byte block boundary (compare to 8 bytes in IP fragmentation).

Fragmentation supports maximum of 64*2^16 = 4 MByte data payloads.

Fragment ID is 16-bit number (0-65535).

Flags:

• LF - last part of current fragment (<Fragment length>+<Fragment offset code> = <Full length of this fragment>)

• EVC - last part of current event (One sets with LF flag for last channel in current event)

• ACK - acknowledge flag: is set in MStream receiver program to inform device of reciecing package which contains fragment with corresponding FragmentId and FragmentOffset

Subtype 0: Trigger and User Data

TAI flags: 2 - timecode is valid, otherwise invalid.

Subtype 1: User Data, Channel-Based Readout

Subtype 2: User Data, Time Slice Based Readout

Acknowledge

Acknowledge package is similar to standard M-Stream package. First 32-bit word should have acknowledge bit up 22^nd bit, as described in Flag field in M-Stream ver. 2.0. All following word will be proceeded as Fragment Id and Fragment Offset pairs. One package can contain one acknowledge pair (by default) or several (request M-Stream configuration register in M-Link CSR).

MLink MStream RawData