CT1611 Datasheet, PDF (13/24 Pages) Aeroflex Circuit Technology – DMA Controller with Buffer Memory,MIL-STD-1750A Compatible

BC Criteria for Valid Transactions
Valid Transactions result in generation of GOOD XFER (INT 0) Interrupt.
Invalid Transfer result in generation of INVALID TRANSFER (INT 1) Interrupt.
See Transaction Word for additional Status Word Criterion (i.e. bit masks)
Transaction Type
1. Normal Data Transfer
A. RT to BC
B. BC to RT
C. Broadcast
Specific Validity Criteria
(Tx/Rx = 1)
(Tx/Rx = 0)
(Tx/Rx = 0)
Status, then Valid Message
Status
No Status
2. RT to RT Transfer
A. Normal
B. Broadcast
3. Mode (no data)
A. Normal
B. Broadcast
4. Mode (associated data)
A. Normal
B. Broadcast
5. Mode (returned data)
(Tx/Rx = 1) Status, Valid Message,then Status
(Tx/Rx = 1) Status, then Valid Message only
Status
No Status
Status
No Status
Status, then returned data
General Validity Criteria - Applies to all transfers
A. Bus must be quiet, i.e. no additional data words, status words or command words after correct RT response
before transaction is declared valid.
B. If data is returned, word count, must be correct. Data must also be contiguous, i.e. no gaps.
C. RTU Address(s) must be correct in returned status word(s).
D. RTU must respond within 14µsec (except for non RT to RT Broadcast).
E. No bits set in returned status word(s), except where masked in transaction word.
BC Interrupt Name
Good Transfer
Invalid Transfer
Poll Operation Complete
SCDCT1611 Rev A
Interrupts In BC Mode
Signal Name
Conditions and Actions
INT 0
1. Indicates fully valid transaction.
2. Initiates next poll operation, when in polling mode.
INT 1
1. Non masked bits set (includes reserved bits).
2. No status (2 for non BCST RT to RT) word returned.
3. Status word has incorrect address.
4. Fail safe time out (1 millisec)for bus (RTU) to go quiet i.e.
RTU loudmouthing.
5. Incorrect number of data words.
6. Busy (even if busy masked) when RTU should receive or
transmit data.
Note: busy mask only masks busy for mode cmds.
INT 2
1. Indicates end of poll,when end of poll is a valid transaction.
2. Delayed from good transfer interrupt.
3. Initiates poll sequence again (from offset) if in continuous
mode.
4. If the I/O command "continue at next transaction" is issued at
the last transaction command, this interrupt will be issued.
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