CT2565 Datasheet, PDF (5/31 Pages) Aeroflex Circuit Technology – CT2565 Bus Controller, Remote Terminal and BUS Monitor FOR MIL-STD-1553B

RECEIVE
Control Word
Receive Command
Data 1
•
•
Last Data
Looped Data Word
RTU Status
TRANSMIT
Control Word
Transmit Command
Looped Command Word
RTU Status
Data 1
•
•
Last Data
Table 3 – BC Memory Allocation
Loop Test
Upon receipt from the subsystem, the last word
to be transmitted within a given message
transfer (command or Data word) is stored in a
CT2565 internal register. As this word is
transmitted to the 1553 bus, it is looped back
through the active receiver channel for auto-BC,
Short Loop verification. A LOOPERR (.5us typ)
low pulse indicates a mismatch between the
stored and looped word. The CT2565 also
initiates a handshake with a memory write to the
subsystem for user-defined, "long loop"
(subsystem, CT2565, subsystem) verification.
Note that both short and long loop testing are
initiated for all transfers (on the last word
transmitted to 1553). Subsystems response to
use Long Loop Test is to compare the loaded
word to what was looped back into memory.
15
8
0
NOT USED
BUS CHANNEL A/B
NOT USED
MASK BROADCAST BIT
NOT USED
MODE CODE
BROADCAST
RT-RT
BIT
DEFINITION
BUS CHANNEL A/B
MASK BROADCAST BIT
MODE CODE
BROADCAST
RT-RT
When logic "1" transmits over 1553 Bus A.
When logic "0" transmits over 1553 Bus B
(See note)
Always set to "0"
Command Word count field signifies mode code type
Multiple RTU’s addressed, no status word expected
When set, RTU(b) transmits, RTU(a) receives. Both RTU Status Words
are validated and sent to subsystem.
Note: Messages-transmission (routing) status pin (pin 16, Chan A/B) becomes active after loading the control word and command word
respectively. The signal is cleared by RESET or EOM low.
Figure 4 – BC Control Word
Aeroflex Circuit Technology
5
SCDCT2565 REV B 8/10/99 Plainview NY [phone]