hi-6131pqtf QuickLogic Corp, hi-6131pqtf Datasheet - Page 161

• Manufacturer Part Number: hi-6131pqtf
• Description: Mil-std-1553 / Mil-std-1760 3.3v Bc / Mt / Rt Multi-terminal Device
• Manufacturer: QuickLogic Corp

from non-broadcast receive commands. Transmit and
receive commands for the same subaddress are illegal-
ized separately. For mode commands, any combination
of mode code number, T/R bit and broadcast/non-broad-
cast status can be legal or illegal.
The Illegalization Table is located in shared RAM within
the fixed address range of 0x0100 to 0x01FF. See Fig-
ure 12. The table is comprised of 256 16-bit words. To
cover the full range of 1 to 32 data words, each subad-
dress uses a pair of illegalization registers. The lower
register (even memory address) covers word counts 0 to
15, using one bit per word count. As in command encod-
ing, “0” denotes 32 data words. Bit 0 corresponds to 32
data words, bit 1 corresponds to 1 data word and bit 15
corresponds to 15 data words. The upper register (odd
memory address) similarly covers word counts 16 to 31,
using one bit per word count. Bit 0 corresponds to 16
data words, while bit 15 corresponds to 31 data words.
When a command’s subaddress field equals 0 or 31
(0x1F), the command is a mode command. Table en-
tries for mode commands use bits to represent mode
code numbers, not word counts. The lower register
(even memory address) covers mode codes 0 to 15, us-
ing one bit per mode code. Bit 0 corresponds to mode
code 0, bit 15 corresponds to mode code 15. The upper
register (odd memory address) similarly covers mode
codes 16 to 31, using one bit per mode code. Bit 0 cor-
responds to mode code 16, bit 15 corresponds to mode
code 31. There is no functional difference between SA0
mode commands and SA31 mode commands. Since
either subaddress indicates a mode command, the sub-
address 0 table words should match the subaddress 31
table words in each quadrant.
Table entries from 0x0142 to 0x017D do not have to be
programmed. These correspond to broadcast transmit
subaddress commands (undefined by MIL-STD-1553B)
and are always invalid. There is no terminal response.
Addressing for the Illegalization Table is derived from
the command word T/R bit, subaddress field, MSB of
the Word Count (Mode Code) field and the command’s
broadcast vs. non-broadcast status as shown below in
Figure 12.
HOLT INTEGRATED CIRCUITS
HI-6130, HI-6131
161
Figure 14 on page 164 shows individual bit locations in the
Illegalization Table for broadcast and non-broadcast
variants of all mode commands defined by MIL-STD-
1553B. Locations are also identified for reserved mode
codes and undefined mode code commands.
The following examples illustrate how the Illegalization
Table is initialized to distinguish between legal and il-
legal commands when “illegal command detection” is
being used. Remember: If the terminal does not use il-
legal command detection, the table is left in its post-MR
reset state, with all table locations reset to 0x0000. In
this case, all command responses are “in form”.
For “subaddress commands” (ordinary receive com-
mands or transmit commands) individual table bits cor-
respond to word counts specified in the received com-
mand word. If a bit is 0, the corresponding word count is
legal. If a bit is 1, the corresponding word count is illegal.
For example, transmit commands to subaddress 1 are
controlled by the words at 0x01C2 and 0x01C3. In Fig-
ure 13 on page 163, these words are located in the “RT
Address Transmit” block. The word stored at 0x01C3
controls subaddress 1 transmit commands having word
counts 16 to 31. The word stored at 0x01C2 controls
subaddress 1 transmit commands having word counts
1 to 15 or 32. (Reminder: In MIL-STD-1553B, zero cor-
responds to 32 words.)
Word at 0x01C3 (Tx Subaddr 1) 31 to 16 words
Bit
Words
Word at 0x01C2 (Tx Subaddr 1) 15 to 1 & 32 words
Bit
Words
If the word stored at 0x01C3 = 0xFFFF and the word
stored at 0x01C2 = 0xFF0F, then commands with 4, 5,
6, or 7 data words are the only legal transmit commands
Address From the Received Command Word
Figure 12. Deriving the Illegalization Table
Bit Fields Comprise Each Received Command Word
0 0 0 0 0 0 0 1
Command
Sync
15 14 13 12 11 10
31 30 29 28 27 26 25 24 23 22 21 20 19 18 17 16
15 14 13 12 11 10
15 14 13 12 11 10
TA4:0 = 11111
Terminal
Address
else “1”
TA4:0
“0” if
T/
Bit
R
9
9
9
Subaddress
8
8
8
SA4:0
7
7
7
6
6
6
5
5
5
(Mode Code)
Word Count
WC4:0
4
4
4
Table
Address
3
3
3
2
2
2
P
1
1
1 32
0
0