ZCOM Tables and Data Structures
Interface Table
driver and the interface card (via “zmon restart”).
ISCHDL - Scheduler event flags
The scheduler uses this word to store the event flags that control the state of the backplane.
Figure | Scheduler Event Flags ISCHDL |
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| 15 | 14 | 13 | 12 | 11 | 10 | 9 | 8 | 7 | 6 | 5 | 4 | 3 | 2 | 1 | 0 |
| AC | ST | NB | PA |
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AC - Driver currently active
ST - Card has sent status transfer request ($STDT)
NB - Driver cannot get any free system buffers
PA - Pause after current event
ITCNTR - Interface terminal counter
The terminal counter is the actual number of terminals defined on this Mux interface card.
IFRTRY - Reset retry count
This is used to count the number of times the Mux interface has been reset due to a backplane timeout, or firmware failure. It is incremented by ZMON each time the Mux card is reset by a request from the DAM. If it reaches an unsatisfactory level, the Mux card will be disabled (set down) by ZMON.
The driver will decrement the retry count if it is not zero after every 30 successful status $STDT replies (i.e., every 5 minutes). If an unstable Mux interface fails and restarts too often, the ZCOM subsystem will mark it as “down” and stop using it.
Chapter 3 | 79 |