Unfortunately I can't offer much help here - if you were using Alta or Condor/SBS/GE 1553 tools I could offer suggestions, but I can't help with DDC. It seems either the PASIT or OAC is not reporting correctly - I'd setup an oscilloscope with one channel on Bus A and another channel on Bus B to verify the message timing. This sounds like a BC programming issue - hopefully DDC tech support can help. Sorry I don't have a more useful suggestion!

Respeted Sir,

Thanks for your reply.I found the above problem is due to Auxclock driver and i solved it.

Now i m facing a new problem.My bus scheduling for 7 minorcycle(140 milliSec) with full load(sync+normal +poll message)and at the start 8th minor cycle sync,(at the completion of one full mojor cycle)it is not able to shcedule the message.

When i schedule only sync it is scheduling for 3 minutes and after that stopped stopped scheduling.Who will be person giving problem either driver of any devie.if so which device or else some other problems.can u guess.

Again, I am not very familiar with the DDC products, but this sounds like a counter problem where the BC stops after sending a given number of messages.

When you send your full frames and it stops after 7 minor frames, how many messages were sent total?

When you have only the sync message and it runs for 3 minutes, how many messages were sent total?

If these two cases send the same number of messages that would indicate that the BC stops when it reaches a specific message count. This would at least narrow down the problem so you can search for issues related to the message count.

The DDC ACE/Mini-ACE Users Guide indicates that BC FRAME AUTOREPEAT MODE uses the INITIAL MESSAGE COUNTER and MESSAGE COUNTER registers. The following is from page 78:

The message count (or initial message count) location must be initialized by the CPU to correspond to the
ones complement of the number of messages to be processed in a message frame. For example, if a
message frame contains one (1) message, the (Initial) Message Counter location should be loaded with a
value of FFFE. The value of the (Initial) Message Counter is incremented by one at the end of each message
processed.

My guess is that your problem is related to these counters.

Respected sir,

Thanks for ur kind replies.we found the above problems are due to the reason:

Reset of 1553B registers is not happened properly.A delay less than 10 microseconds after reset command make the system to work perfectly.

Again thanks for ur replies.