CT2566 Datasheet, PDF (16/37 Pages) Aeroflex Circuit Technology – CT2566 MIL-STD-1553 to Microprocessor Interface Unit

MT Operation
The MT mode is selected by setting bit 15 of the
Configuration Register to logic "0" and bit 14 to a
logic "1" along with issuing a Controller Start
Command.
START
ISSUE RESET COMMAND
Word. The RAM automatically wraps around (from
location FFFF to location 0000), shown in Figure 20.
Bit 7 of the Identification Word can be reset by the
CPU each time it reads the associated data word into
CPU memory. This provides a simple method of
keeping track of words that have been processed by
the CPU.
15
87
0
1
GAP TIME
111
CLEAR RAM
INITIALIZE STACK POINTER
SET CONFIGURATION REGISTER
TO MT MODE
SET TO "1"
ERROR (1 = ERROR, 0 = GOOD STATUS)
COMMAND SYNC
1553 CHANNEL A/B
WORD GAP
SET TO "0"
Note: Each bit of the GAP TIME field
represents .5µs.
Figure 19 – MT Identification Word
ISSUE START COMMAND
Figure 18 – MT Initialize
(under user control)
MT Initialization
For MT operations, the entire RAM is used as the MT
Stack (See Table 5) and the setups shown in Figure 18
are followed. The user instructs the CT2566 where to
store the first received 1553 word by loading the
starting word address in the Stack Pointer. Once a
Controller Start command is issued, the CT2566 will
store this value in the internal Address Register.
The identification Word provides the CPU with
additional information regarding the received 1553
word, its format is shown in Figure 19. This information
allows the user to develop algorithms to restructure the
message transfers. External Logic can be used for
triggering on specific commands or subaddresses. For
further information, consult factory.
The 1553 device will generate an Identification Word
for every word that is transferred across the 1553 Data
Bus. The CT2566 stores the received 1553 word in the
RAM location indicated by the internal Address
Register. The contents of this register are incremented
by one so that it points to the next word in RAM, and
the Identification Word is stored at that location. The
internal Address Register is then incremented by one
again, in preparation for storing the next Identification
START COMMAND ISSUED
GET STACK POINTER FROM
WORD 100 IN RAM AND
STORE IN INTERNAL REGISTER
WORD TRANSFERRED
NO
ACROSS 1553 BUS
?
YES
STORE RETREIVED 1553 WORD
IN RAM, INCREMENTS INTERNAL
ADDRESS REGISTER
STORE IDENTIFICATION WORD
IN RAM, INCREMENT INTERNAL
ADDRESS REGISTER
Figure 20 – MT Sequence of Operation
(under CT2566 control)
Aeroflex Circuit Technology
16
SCDCT2566 REV B 8/10/99 Plainview NY [phone]