CRKit R4 VITA Specrev 0.1

WINLAB – Rutgers University

Date : May 20 2011

VITA Data Packet

PKT_TYPE : 0000 - IF Data packet w/o sID0001 - IF Data packet w sID0010 - Extension Data packet w/o sID0011 - Extension Data packet w sID (supported in R4)0100 - IF Context packet0101 - Extension Contect packetOthers - reserved

C == 0, no Class Identifier field

T == 0, no Trailer included

TSI :00 - no integer-seconds timestamp field01 - Coordinated Universal Time (UTC)10 - GPS time11 - Other (supported in R4, second ticks)

TSF :00 - No fractional-seconds timestamp field01 - sample count timestamp (supported in R4)10 - Real time (ps) timestamp11 - free running count timestamp

PKT_CNT : Packet counter, wraps around e.g. 0x0 -> 0xF -> 0x0Counter is linked to same sID and PKT_TYPE (different counter for different sID)

PKT_SIZE : Packet size, number of 32-bit words (header + optional fields + payload). Here, header + optional fields = 5 words.

Time Generator

@100MHz, 1 sec = 108 clock ticks

Number of seconds, wraps around e.g. 0xFFFFFFFF -> 0x00000000

Number of clock ticks, 1sec =108 = 0x5F5E100.CLOCK_CNT range = 0x0 -> 0x5F5E0FF(27-bit counter, other 64-27 = 37 bits are NULL)

VITA Context Packet

PKT_TYPE : (2 choices) 0100 - IF Context packet0101 - Extension Contect packet

C == 0, no Class Identifier field

TSM == 0, time stamp used to convey precise timing of events or context changes

TSI == b11, Other – number of seconds (same as for paired data packet)

TSF == b01, sample count time stamp (same as for paired data packet)

sID – same as for paired data packet

No context indicator field for Extension Context packet. For IF context packet, the context-indicator field indicates which of the VITA standard control fields are present in the context message. See standard for further information.

We assume that the context content is parsed by software.

VITA Emitter

Cache last entry to avoid memory access

read, increment and write-back. Note : incr + WB only if V == 1

Select Payload by default. Only insert header + timestamp fields when requested by Emitter CTL.

IP processor ready to acceptUDP payload e.g. VITA payload

Only applicable to Context packets

Prefetch next lookup table entry during current payload transfer

MMU data ready

VITA Receiver

UDP 1000Payload

Lookup using incoming sID e.g. direct-mapped

VITA header + payload

VITA payload only

Delay line to line up data and portID.However, may not be necessary as VITA header + sID + timestamp fields are not forwarded to MMU. Use gap to fetch portID from lookup table.

If (PKT_TYPE == 0100 OR PKT_TYPE == 0101) then

CONTEXT PACKET -> PCORE

else

DATA PACKET -> MMU

endif;

Cache last entry to avoid memory access

Provide portID one clock ahead of payload to preset port at MMU

Open issue : how to use timestamp information ?