Data Device Corporation
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3
MIL-STD-1553 MODES AND ARCHITECTURE
3.1 Bus Controller Mode
The
Total-AceXtreme’s
MIL-STD-1553 Bus Controller (BC) is based on the 32-bit
architecture of DDC’s
AceXtreme
1553 Bus Controller.
Total-AceXtreme’s
BC architecture retains much of the previous generation
(Enhanced Mini-ACE, Mini-ACE Mark 3, Micro-ACE (TE), and Total-ACE) 1553 Bus
Controller architecture. However, it expands upon it in specific areas to provide
improved capabilities. The top-level BC design, shown in Figure 3, includes the
Command Interpreter, Low and High Priority Queues (LPQ and HPQ respectively),
1553 Protocol engine, and General Purpose Queue (GPQ).
The
Total-AceXtreme®
BC architecture is based on a built-in command interpreter
with a set of 32 instructions. The command interpreter is a message sequence
control engine that provides a high degree of flexibility for implementing 1553
Message lists, including major and minor frame scheduling. It separates 1553
message data from control/status data for the purposes of implementing different
data block handling schemes, performing bulk data transfers, and implementing
automatic message retries. It also includes the capability for automatic bus
switchover for failed messages and reporting of various error and status conditions to
the host processor by means of five user-defined interrupts and a general-purpose
queue.
Two Asynchronous queues are also included, to improve the Bus Controller’s
efficiency and flexibility. The High Priority Queue (HPQ) enables the user to easily
insert asynchronous messages into a running Message list, causing it to operate on
the new message immediately. The Low Priority Queue (LPQ) enables the user to
insert asynchronous messages which will only be processed when there’s sufficient
“dead-time” available on the bus at the end of a minor frame.
The
Total-AceXtreme’s
BC Engine implements all MIL-STD-1553B message
formats. Message format is programmable on a message-by-message basis.
Automatic retries and interrupt requests may be enabled or disabled for each
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 BC No-Response timeout value is also
programmable to enable operation over long buses or through repeaters.