ibaLink-VME
Manual
Issue 1.8
55
Example 2: System Topology for Daisy-Chain of 3 ibaLink-VME with different
ranges
Figure 25 Cascade mode with 3 x ibaLink-VME
Three ibaLink-VME interface cards are daisy-chained, transmitting different amounts of
data.
Card #1 transmits 2 containers and occupies the first two slots;
card #2 transmits 2 containers and occupies the next two slots;
card #3 transmits 4 containers, but the address switch is set to 4. So a slot, already filled
with data from card #2, is overwritten. Since the last participant in a daisy-chain is dom-
inant, a container of card #2 gets lost. In order to avoid this, the address switch of card
#3 should point on 5.
Flow of Data Considerations
Be careful to note that the data is written to each ibaLink-VME local dual port RAM.
Consider the example above, card #2 receives 16 signals from card #1, card #3 re-
ceives 16 signals from card #1 and 16 signals from card #2.
When two ranges overlap each other, the 2 x 8 signals will get to the DPR of card #3,
but card #3 overwrites the last signals of card #2 with own signals. So only 8 signals of
card #2 reach the FOB card, although the signals are transferred from card #2 to card
#3.
ibaLink-VME #3 overwrites
8 signals of the previous
ibaLink-VME card #2.
