CT2565 Aeroflex Circuit Technology, CT2565 Datasheet - Page 13

• Manufacturer Part Number: CT2565
• Description: CT2565 Bus Controller/ Remote Terminal and BUS Monitor FOR MIL-STD-1553B
• Manufacturer: Aeroflex Circuit Technology

Aeroflex Circuit Technology
Mode Code Illegalization (Optional)
The word count and TX/RX pins will be latched
800ns (typ) after the falling edge of NBGRNT
(See Figure 13, RTU Command Word Handling).
Table 5 lists the CT2565 pins associated with
mode code illegalization. If the current command
is a mode code, LMC (pin 55) will go high. Mode
codes can be illegalized, using an external PROM
(<200ns access time recommended), by setting
ILLCMD low after the NBGRNT flag. This will set
the message error (status word) and illegal Mode
Code (BIT word) bits followed by transmission of
the status word.
commands can be "auto-screened" without
interrupting subsystem operation. For a complete
list of mode codes, refer to Table 8.
STATUS INPUTS
Note: Memory read/write signals CS, OE, and ADRINC remain static at logic "1".
Status Inputs
WC
NBGRNT (42)
Illegalize
BUSREQ (19)
BUSACK (59)
ILLCMD (48)
Legal
0-4
INCMD (9)
SOM (78)
LMC (55)
D0 - D15
T/R (15)
SYM
Figure 13 – RTU Command Word Handling/Status Inputs
t1
t2
t3
t4
t5
t6
t7
t8
t9
Using the method, mode
DBACCEPT, SSFLAG, SVCREQ, SSER and SSBUSY INPUTS
t
t
2
DESCRIPTION
1
NBGRNT pulse width
NBGRNT to LMC delay
NBGRNT to INCMD delay
BUSACK to SOM delay
SOM pulse width
CMD VALID setup
NBGRNT low to status latch
LMC to WC-T/R latch
LMC to ILLCMD latch
t
3
t
4
t
5
VALID UNTIL NEXT VALID COMMAND WORD RECEIVED
LATCHED UNTIL NEXT VALID COMMAND WORD RECEIVED
13
Note: A word count field of all 0’s indicates 32 data words; all 1’s
PIN #
51
12
52
13
53
15
t
= 31 words.
9
Table 5 – Mode Code Illegalization
MIN
151
500
60
-
-
-
-
-
-
SYMBOL
WC0
WC1
WC2
WC3
WC4
T/R
t
6
CMD VALID
SCDCT2565 REV B 8/10/99 Plainview NY [phone]
TYP
200
166
166
t
1.0
7
-
-
-
-
-
t
8
Word Count LSB
Word Count 1
Word Count 2
Word Count 3
Word Count MSB
TX/RX
DESCRIPTION
MAX
181
667
333
100
1.5
3
-
-
-
UNITS
LATCHED
ns
ns
ns
ns
µs
ns
ns
ns
µs