Start/Reset Register: Used for "command" type functions, such
as software reset, BC/MT Start, Interrupt Reset, Time Tag
Reset, and Time Tag Register Test. The Start/Reset Register
includes provisions for stopping the BC in its auto-repeat mode,
either at the end of the current message or at the end of the cur-
rent BC frame.
For BC mode, the enhanced mode features include the expand-
ed BC Control Word and BC Block Status Word, additional Stop-
On-Error and Stop-On-Status Set functions, frame auto-repeat,
programmable intermessage gap times, automatic retries,
expanded Status Word Masking, and the capability to generate
interrupts following the completion of any selected message.
BC/RT Command Stack Pointer Register: Allows the host
CPU to determine the pointer location for the current or most
recent message when the PC Card is in BC or RT mode.
For RT mode, the enhanced mode features include the expand-
ed RT Block Status Word, the combined RT/Selective Message
RTFAIL
" output signal
Monitor mode, internal wrapping of the "
RTFLAG
(from the J' chip)to the "
" RT Status Word bit, the double
BC Control Word/RT Subaddress Control Word Register:
In BC mode, allows host access to the current or most recent BC
Control Word. The BC Control Word contains bits that select the
active bus and message format, enable off-line self-test, mask-
ing of Status Word bits, enable retries and interrupts, and spec-
ify MIL-STD-1553A or -1553B error handling. In RT mode, this
register allows host access to the current or most recent
Subaddress Control Word. The Subaddress Control Word is
used to select the memory management scheme and enable
interrupts for the current message. The read/write accessibility
can be used as an aid for testing the ACE.
buffering scheme for individual receive (broadcast) subaddress-
es, and the alternate (fully software programmable) RT Status
Word.
For MT mode, use of the enhanced mode enables use of the
Selective Message Monitor, the combined RT/Selective Monitor
modes, and the monitor triggering capability.
Data Stack Address Register: Used to point to the current
address location in shared RAM used for storing message words
(second Command Words, Data Words, RT Status Words) in the
Selective Word Monitor mode.
Time Tag Register: Maintains the value of a real-time clock.
The resolution of this register is programmable from among 2, 4,
8, 16, 32, and 64 µs/LSB. The TAG_CLK input signal also may
cause an external oscillator to clock the Time Tag Register.
Start-of-Message (SOM) and End-of-Message (EOM)
sequences in BC, RT, and Message Monitor modes cause a
write of the current value of the Time Tag Register to the stack
area of RAM.
Frame Time Remaining Register: Provides a read only indi-
cation of the time remaining in the current BC frame. The reso-
lution of this register is 100 µs/LSB.
Message Time Remaining Register: Provides a read only indi-
cation of the time remaining before the start of the next message
in a BC frame. The resolution of this register is 1 µs/LSB.
BC Frame/RT Last Command/MT Trigger Word Register:
In BC mode, it programs the BC frame time for use in the frame
auto-repeat mode. The resolution of this register is 100 µs/LSB,
with a range of 6.55 seconds. In RT mode, this register stores
the current (or most previous) 1553 Command Word processed
by the ACE RT; in the Word Monitor mode, this register specifies
a 16-bit Trigger (Command) Word. The Trigger Word may be
used to start or stop the monitor, or to generate interrupts.
Interrupt Status Register: Mirrors the Interrupt Mask Register
and contains a Master Interrupt bit. It allows the host processor
to determine the cause of an interrupt request by means of a sin-
gle READ operation.
Configuration Registers #3, #4, and #5: Used to enable many
of the BU-65552, BU-65551 and BU-65550 advanced features.
These include all the enhanced mode features; that is, all the
functionality beyond that of the previous generation product, the
BUS-65529 that makes use of the Advanced Integrated Mux
Hybrid with Enhanced RT Features (AIM-HY'er). For all three
modes, use of the Enhanced Mode enables the various read-
only bits in Configuration Register #1.
Status Word Register and BIT Word Registers: Provide read-
only indications of the BU-65552, BU-65551 and BU-65550 RT
Status and BIT Words.
Test Mode Registers 0-7: These registers may be used to facil-
itate built-in testing of the BU-65552, BU-65551 and BU-65550 .
5
ETC [ ETC ]
