BU-61582 データシートの表示（PDF） - Unspecified
部品番号
コンポーネント説明
メーカー
BU-61582 Datasheet PDF : 48 Pages
| |||
BC CONTROLLER (BC) ARCHITECTURE
The BC protocol of the BU-61582 implements all MIL-STD-
1553B message formats. Message format is programmable on a
message-by-message basis by means of bits in the BC Control
Word and the T/R bit of the Command Word for the respective
message. The BC Control Word allows 1553 message format,
1553A/B type RT, bus channel, self-test, and Status Word mask-
ing to be specified on an individual message basis. In addition,
automatic retries and/or interrupt requests may be enabled or
disabled for individual messages. The BC performs all error
checking required by MIL-STD-1553B. This includes validation of
response time, sync type and sync encoding, Manchester II
encoding, parity, bit count, word count, Status Word RT Address
field, and various RT-to-RT transfer errors. The BU-61582’s BC
response timeout value is programmable with choices of 18, 22,
50, and 130 µs. The longer response timeout values allow for
operation over long buses and/or the use of repeaters.
FIGURE 2 illustrates BC intermessage gap and frame timing.
The BU-61582 may be programmed to process BC frames of up
to 512 messages with no processor intervention. It is possible to
program for either single frame or frame auto-repeat operation.
In the auto-repeat mode, the frame repetition rate may be con-
trolled either internally, using a programmable BC frame timer, or
from an external trigger input. The internal BC frame time is pro-
grammable up to 6.55 seconds in increments of 100 µs. In addi-
tion to BC frame time, intermessage gap time, defined as the
start of the current message to the start of the subsequent mes-
sage, is programmable on an individual message basis. The time
between individual successive messages is programmable up to
65.5 ms, in increments of 1 µs.
BC MEMORY ORGANIZATION
TABLE 27 illustrates a typical memory map for BC mode. It is
important to note that the only fixed locations for the BU-61582
in the Standard BC mode are for the two Stack Pointers (address
locations 0100 (hex) and 0104) and for the two Message Count
locations (0101 and 0105). Enabling the Frame Auto-Repeat
mode will reserve four more memory locations for use in the
Enhanced BC mode; these locations are for the two Initial Stack
Pointers (address locations 102 (hex) and 106) and for the Initial
TABLE 27. TYPICAL BC MEMORY ORGANIZATION
(SHOWN FOR 16K RAM)
ADDRESS
(HEX)
DESCRIPTION
0000-00FF Stack A
0100 Stack Pointer A (fixed location)
0101 Message Count A (fixed location)
0102
Initial Stack Pointer A (see note)
(Auto-Frame Repeat Mode)
0103
0104
Initial Message Count A (see note)
(Auto-Frame Repeat Mode)
Stack Pointer B
0105 Message Count B
0106
Initial Stack Pointer B (see note)
(Auto-Frame Repeat Mode)
0107
Initial Message Count B (see note)
(Auto-Frame Repeat Mode)
0108-012D Message Block 0
012E-0153 Message Block 1
0154-0179 Message Block 2
•
•
•
•
•
•
3EC8-3EED Message Block 416
3EEE-3EFF Not Used
3F00-3FFF Stack B
Note: Used only in the Enhanced BC mode with Frame Auto-Repeat enabled.
Message Count locations (103 and 107). The user is free to
locate the Stack and BC Message Blocks anywhere else within
the 64K (16K internal) shared RAM address space.
For simplicity of illustration, assume the allocation of the maxi-
mum length of a BC message for each message block in the typ-
ical BC memory map of TABLE 27. The maximum size of a BC
message block is 38 words, for an RT-to-RT transfer of 32 Data
Words (Control + 2 Commands + Loopback + 2 Status Words +
32 Data Words). Note, however, that this example assumes the
disabling of the 256-word boundaries.
MESSAGE
GAP TIME
FOR MESSAGE NO. 1
INTERMESSAGE GAP TIME
MESSAGE NO. 1
MESSAGE NO. 2
Data Device Corporation
www.ddc-web.com
BC FRAME TIME
FIGURE 2. BC MESSAGE GAP AND FRAME TIMING
13
MESSAGE NO. 1
BU-61582
M-08/04-0
Share Link: 