VLYNQ Port User's Guide

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A.5 VLYNQ 2.X Packets
VLYNQ 2.X Packets
An example of what can happen to a write burst due to remote and local FIFO state changes and the link
pulse timer expiring is shown in Example A-1 . This protocol can be extended to apply to multiple channels;
therefore, the data return channel is logically isolated from the command channel.
Example A-1. A write burst due to remote and local FIFO state changes and the link pulse timer
expiring
Basic packets:
Read32 - caaaaT
Write32 - caaaaddddT
ReadCfg - claaaaT
WriteCfg - claaaadddd ddddT
ReadBurst - claaaaT
WriteBurst - claaaadddddddd ddddT
Int - cddddT
ReadReturn - cldddd ddddT
Where
I - Idle
T - EndOfPacket
d - data
a - address
c - command
l - length
M - Byte mask
I[#] - Flowed, # is used when exiting flowed for a channel, the # is actually the current
channel command.
P# - Flow Enable for a channel
C# - Flow Disable for a channel
L - Link pulse
and what is in italics is optional data up to 16 words total.
Packet with byte enables:
WriteBurst - claaaaMMddMMdd MMddT
The above packet wrote to the LS half words from the specified address.
Packet that has been flowed due to remote FIFO status:
WriteBurst - claaaaMMddM IIIIIIIIIIIII#Mdd MMddT
The packet was extended using the I code. The # is used to
indicate that the same channel was continued.
To the same packet, the potential flowing of the local FIFO’s is added:
WriteBurst - claaaaMMddMIIP# IIIIIIIIIIIII#Mdd MMdC# dT
Link pulse to the stream is added:
WriteBurst - claaLaaMMddMIIP# IIIIIIIIIII#Mdd MMdC# dT
An example of a write burst flowed and interrupted by a read return data burst is shown below. In the
example, a 1 indicates a data return channel (it is actually the return data command) and a 0 indicates a
command channel, which is the command for the transaction.
IIIIclaaaadddd Iclddd III1dddd II0ddddddddddddd IIIIII0dddT IIIII1dT IIII
42 VLYNQ Protocol Specifications SPRU938B – September 2007
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