H A R D W A R E O P E R A T I O N
Data Device Corporation
BU-65570/2i Manual
23
RT MODE
The BU-65572iX can simultaneously simulate the operation of 31 unique
remote terminals (RTs) plus a broadcast address for each of the
installed channels. The BU-65572iX maintains "last status" and "last
command" words allowing for full support of transmit last command and
transmit status mode commands. The BU-65572iX supports full RT
command illegalization for each transmit or receive message based on
RT address and sub-address. In addition, individual mode commands
may be illegalized.
RT Error Injection
Error conditions may be injected on an individual RT/SA basis. The
BU-65572iX supports five categories of injected RT errors: length errors,
encoding errors, gap errors, status address errors, and response errors.
Length errors include both word count errors and bit count errors. Word
counts of -32 to +1 words may be programmed. Bit counts of +3, +2, +1,
-3, -2, or -1 bit may be programmed on any word within the message.
Error specifications are attached to the data tables that are mapped to a
RT and Sub-address combination. This provides for a large number of
possibilities for injecting errors. An application can map more than one
data table to any given RT/SA combination. This means that the RT can
respond with different errors each time it is accessed.
Encoding errors are implemented though the use of two simple yet
powerful mechanisms for modifying the output of the BU-65572i's
Manchester encoder. The two modifying functions are glitch and inverse.
A glitch will force the output of the encoder to an idle bus condition for
the specified period of time. An inverse will invert the output of the
encoder for the specified period of time. The word number, starting time,
and width specify the placement of this error. The error may be placed in
any word within the message. The starting time is programmed in 500
nsec increments from the beginning of the specified word. The width of
the error is specified in 50 nsec increments up to 3
µ
sec. This error
injection scheme lends itself to generating a host of errors including
invalid sync patterns, parity errors, and Manchester bi-phase errors.
A gap of 3, 4, or 5
µ
sec (measured mid parity crossing to mid-sync
crossing) may be inserted between any two words in message. This
allows for a "dead time" gap between words of 1, 2, or 3
µ
sec. A status
address error may be injected in which the RT responds with a status
word containing a RT address, which does not match the terminal's RT
address. The RT may be programmed to respond with any value from
zero to 31 in its status response.
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