BU-61582 データシートの表示（PDF） - Unspecified
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BU-61582 Datasheet PDF : 48 Pages
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these words may be formulated in real time by the BU-61582
protocol logic.
The BU-61582 RT protocol design implements all the MIL-STD-
1553B message formats and dual redundant mode codes. This
design is based largely on previous generation products that
have passed SEAFAC testing for MIL-STD-1553B compliance.
The SP’ACE RT performs comprehensive error checking, word
and format validation, and checks for various RT-to-RT transfer
errors. Other key features of the BU-61582 RT include a set of
interrupt conditions, internal command illegalization, and pro-
grammable busy by subaddress.
RT MEMORY ORGANIZATION
TABLE 28 illustrates a typical memory map for the SP’ACE in RT
mode. As in BC mode, the two Stack Pointers reside in fixed
locations in the shared RAM address space: address 0100 (hex)
for the Area A Stack Pointer and address 0104 for the Area B
Stack Pointer. Besides the Stack Pointer, for RT mode there are
several other areas of the BU-61582 address space designated
as fixed locations. All RT modes of operation require the Area A
and Area B Lookup Tables. Also allocated, are several fixed loca-
tions for optional features: Command Illegalization Lookup Table,
Mode Code Selective Interrupt Table, Mode Code Data Table,
and Busy Bit Lookup Table. It should be noted that any unen-
abled optional fixed locations may be used for general purpose
storage (data blocks).
The RT Lookup tables, which provide a mechanism for mapping
data blocks for individual Tx/Rx/Bcst-subaddresses to areas in
the RAM, occupy address range locations 0140 to 01BF for Area
A and 01C0 to 023F for Area B. The RT lookup tables include
Subaddress Control Words and the individual Data Block
Pointers. If used, address range 0300-03FF will be dedicated as
the illegalizing section of RAM. The actual Stack RAM area and
the individual data blocks may be located in any of the nonfixed
areas in the shared RAM address space.
RT MEMORY MANAGEMENT
Another salient feature of the SP’ACE series products is the flexi-
bility of its RT memory management architecture. The RT architec-
ture allows the memory management scheme for each transmit,
receive, or broadcast subaddress to be programmable on a sub-
address basis. Also, in compliance with MIL-STD-1553B Notice 2,
the BU-61582 provides an option to separate data received from
broadcast messages from nonbroadcast received data.
Besides supporting a global double buffering scheme (as in BC
mode), the SP’ACE RT provides a pair of 128-word Lookup
Tables for memory management control, programmable on a
subaddress basis (refer to TABLE 29). The 128-word tables
include 32-word tables for transmit message pointers and
receive message pointers. There is also a third, optional Lookup
Table for broadcast message pointers, providing Notice 2 com-
pliance, if necessary.
TABLE 28. TYPICAL RT MEMORY MAP
(SHOWN FOR 16K RAM)
ADDRESS
(HEX)
DESCRIPTION
0000-00FF
Stack A
0100
Stack Pointer A (fixed location)
0101-0103
RESERVED
0104
Stack Pointer B (fixed location)
0105-0107
RESERVED
0108-010F
Mode Code Selective Interrupt Table (fixed area)
0110-013F
Mode Code Data (fixed area)
0140-01BF
Lookup Table A (fixed area)
01C0-023F
Lookup Table B (fixed area)
0240-0247
Busy Bit Lookup Table (fixed area)
0248-025F
(not used)
0260-027F
Data Block 0
0280-02FF
Data Block 1-4
0300-03FF
Command Illegalizing Table (fixed area)
0400-041F
Data Block 5
0420-043F
Data Block 6
•
•
•
•
•
•
3FE0-3FFF
Data Block 476
The fourth section of each of the RT Lookup Tables stores the 32
Subaddress Control Words (refer to TABLE 11 and TABLE 30).
The individual Subaddress Control Words may be used to select
the RT memory management option and interrupt scheme for
each transmit, receive, and (optionally) broadcast subaddress.
For each transmit subaddress, there are two possible memory
management schemes: (1) single message; and (2) circular
buffer. For each receive (and optionally broadcast) subaddress,
AREA A
0140
.
.
.
015F
0160
.
.
.
017F
0180
.
.
.
019F
01A0
.
.
.
01BF
TABLE 29. LOOK-UP TABLES
AREA B
DESCRIPTION COMMENT
01C0
.
.
.
01DF
Rx(/Bcst)_SA0
.
.
.
Rx(/Bcst)_SA31
Receive
(/Broadcast)
Lookup Table
01E0
.
.
.
01FF
Tx_SA0
.
.
.
Tx_SA31
Transmit
Lookup Table
0200
.
.
.
021F
Bcst_SA0
.
.
.
Bcst_SA31
Broadcast
Lookup Table
Optional
0220
.
.
.
023F
SACW_SA0
.
.
.
SACW_SA31
Subaddress
Control Word
Lookup Table
(Optional)
Data Device Corporation
www.ddc-web.com
16
BU-61582
M-08/04-0
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