CT2566 Datasheet, PDF (11/37 Pages) Aeroflex Circuit Technology – CT2566 MIL-STD-1553 to Microprocessor Interface Unit

BC Operation
The BC mode is selected by setting the two MSBs of
the Configuration Register to logic "0". This can be done
by writing directly to the register or by issuing a
MSTRCLR or RESET command. Note that a RESET
will also clear the Interrupt Mask Register.
BC Initialization.
For BC operation, the user initializes the RAM as
shown in Table 3 and follows the steps in Figure 11, BC
Initialization. The CPU loads the data blocks with 1553
messages (See Figure 12). The first word of each data
block must contain the Control Word (shown in Figure
13) for the message. The starting addresses of the data
blocks are placed in the fourth word of the Descriptor
Stack in the order the messages are to be transmitted
(i.e. the address of the first message is loaded into the
fourth location of the Stack, the address of the second
message is placed into the eighth location, etc). Once
the data blocks and the Descriptor Stack have been
initialized, the CPU loads the current area message
count with the number of messages to transfer (load in
1’s complement).
CONTROL
WORD
CONTROL
WORD
CONTROL
WORD
CONTROL
WORD
Table 3 - Typical BC Memory Map
(4K memory)]
HEX ADDRESS
FUNCTION
Fixed Areas
0100
0101
0104
0105
Stack Pointer A
Message Count A
Stack Pointer B
Message Count B
User Defined Areas
0108-013F
0140-017F
0180-01BF
01C0-01FF
•
•
0F00-0FFF
0000-00FF
Not Used
Data Block 1
Data Block 2
Data Block 3
•
•
Descriptor Stack A
Descriptor Stack B
CONTROL
WORD
CONTROL
WORD
CONTROL
WORD
BROADCAST
COMMAND
BROADCAST
COMMAND
(NO DATA)
RECEIVE
COMMAND
TRANSMIT
COMMAND
RECEIVE
COMMAND
MODE
COMMAND
MODE
COMMAND
MODE
COMMAND
DATA WORD
1
BROADCAST
COMMAND
LOOPED
BACK BY
CT2565
BROADCAST
COMMAND
(NO DATA)
DATA WORD
1
DATA WORD
2
TRANSMIT
COMMAND
LOOPED
BACK BY
CT2565
STATUS
RECEIVED
TRANSMIT
COMMAND
TRANSMIT
COMMAND
LOOPED
BACK BY
CT2565
DATA WORD
DATA WORD
LOOPED
BACK BY
CT2565
MODE
COMMAND
LOOPED
BACK BY
CT2565
STATUS
WORD
MODE
COMMAND
LOOPED
BACK BY
CT2565
STATUS
WORD
DATA WORD
2
DATA WORD
LAST
DATA WORD
LAST
DATA WORD
1
STATUS
WORD 1
FROM XMTR
DATA WORD
LAST
LOOPED
BACK BY
CT2566
DATA WORD
2
DATA WORD
1 RECEIVED
STATUS
WORD
DATA WORD
RECEIVED
MODE CODE
WITHOUT
DATA
MODE CODE
WITH DATA
RECEIVE
DATA BLOCK
FORMAT
MODE CODE
WITH DATA
TRANSMIT
DATA BLOCK
FORMAT
DATA WORD
LOOPED
BACK BY
CT2565
BROADCAST
COMMAND
WITH DATA
STATUS
RECEIVE
DATA WORD
LAST
DATA WORD
2 RECEIVED
Aeroflex Circuit Technology
RECEIVE
TRANSMIT
DATA BLOCK DATA BLOCK
LAST DATA
WORD
RECEIVED
STATUS
WORD 2
FROM
RECEIVER
REMOTE
TERMINAL TO
REMOTE
TERMINAL
DATA BLOCK
Figure 12 – BC Message Data Block Formats
11
SCDCT2566 REV B 8/10/99 Plainview NY [phone]