9
Data Device Corporation
www.ddc-web.com
BU-6474X/6484X/6486X
AL-11/12-0
INTRODUCTION
The Mini-ACE Mark3 is the world's first MIL-STD-1553 terminal
which can be powered entirely by 3.3 volts, thus eliminating the
need for a 5 volt power supply. The BU-6474X RT only, and
BU-6484X/6486X BC/RT/MT Mini-ACE Mark3 family of MIL-
STD-1553 terminals comprise a complete integrated interface
between a host processor and a MIL-STD-1553 bus. The Mini-ACE
Mark3 is available in a 0.88 square inch flat pack or gull wing pack-
age with a "toe-to-toe" dimension of 1.110 inches, as well as a 324-
ball BGA. The Mini-ACE Mark3 is the industry's smallest ceramic
gull-lead 1553 terminal, enabling its use in applications where PC
board space is at a premium. At 0.815 inches square, the Micro-
ACE-TE provides the smallest MIL-STD-1553 footprint in the indus-
try. The Mark3's architecture is identical to that of the Enhanced
Mini-ACE, and most features are functionally and software compat-
ible with the previous Mini-ACE (Plus) and ACE generations.
The Mini-ACE Mark3 provides complete multiprotocol support of
MIL-STD-1553A/B/McAir and STANAG 3838. The Mark3 integrates
dual transceiver, protocol logic, and either 4K or 64K words of internal
RAM. The BU-6486X BC/RT/MT terminal includes 64K words of
internal RAM, with built-in parity checking.
The Mini-ACE Mark3 includes dual 3.3 volt or 5.0 volt voltage
source transceivers for improved line driving capability, with
options for MIL-STD-1760 and McAir compatibility. Mark3 ver-
sions with 64K x 17 RAM and all versions of the Micro-ACE-TE
with the 8/9 transceiver option offer an additional transceiver
power-down (SLEEPIN) option to further reduce device power
consumption. To provide further flexibility, the Mini-ACE Mark3
may operate with a choice of 10, 12, 16, or 20 MHz clock inputs.
One of the new salient features of the Mark3 is its Enhanced bus
controller architecture. The Enhanced BC's highly autonomous
message sequence control engine provides a means for offloading
the host processor for implementing multiframe message schedul-
ing, message retry schemes, data double buffering, and asynchro-
nous message insertion. For the purpose of performing messaging
to the host processor, the Enhanced BC mode includes a General
Purpose Queue, along with user-defined interrupts.
A second major new feature of the Mark3 is the incorporation of
a fully autonomous built-in self-test. This test provides compre-
hensive testing of the internal protocol logic. A separate test
verifies the operation of the internal RAM. Since the self-tests are
fully autonomous, they eliminate the need for the host to write
and read stimulus and response vectors.
The Mini-ACE Mark3 RT offers the same choices of single, dou-
ble, and circular buffering for individual subaddresses as the
ACE, Mini-ACE (Plus) and Enhanced Mini-ACE. New enhance-
ments to the RT architecture include a global circular buffering
option for multiple (or all) receive subaddresses, a 50% rollover
interrupt for circular buffers, an interrupt status queue for logging
up to 32 interrupt events, and an option to automatically initialize
TABLE 1 Notes:
Notes 1 through 6 are applicable to the Receiver Differential Resistance
and Receiver Differential Input Capacitance specifications:
(1) Specifications include both transmitter and receiver (tied together
internally).
(2) Impedance parameters are specified directly between pins TX/
RX_A(B) and TX/RX_A(B) of the Mini-ACE Mark3 hybrid.
(3) It is assumed that all power and ground inputs to the hybrid are
connected.
(4) The specifications are applicable for both unpowered and powered
conditions.
(5) The specifications assume a 2 volt rms balanced, differential, sinu-
soidal input. The applicable frequency range is 75 kHz to 1 MHz.
(6) Minimum resistance and maximum capacitance parameters are
guaranteed over the operating range, but are not tested.
(7) Assumes a common-mode voltage within the frequency range of dc
to 2 MHz, applied to pins of the isolation transformer on the stub
side (either direct or transformer coupled), and referenced to hybrid
ground. Transformer must be a DDC recommended transformer or
other transformer that provides an equivalent minimum CMRR.
(8) Typical value for minimum intermessage gap time. Under software
control, this may be lengthened (to 65,535 ms - message time) in
increments of 1 µs. If ENHANCED CPU ACCESS, bit 14 of
Configuration Register #6, is set to logic "1", then host accesses
during BC Start-of-Message (SOM) and End-of-Message (EOM)
transfer sequences could have the effect of lengthening the inter-
message gap time. For each host access during an SOM or EOM
sequence, the intermessage gap time will be lengthened by 6 clock
cycles. Since there are 7 internal transfers during SOM and 5 dur-
ing EOM, this could theoretically lengthen the intermessage gap by
up to 72 clock cycles; i.e., up to 7.2 ms with a 10 MHz clock, 6.0 µs
with a 12 MHz clock, 4.5 µs with a 16 MHz clock, or 3.6 µs with a
20 MHz clock.
(9) For Enhanced BC mode, the typical value for intermessage gap
time is approximately 10 clock cycles longer than for the non-
enhanced BC mode. That is, an addition of 1.0 µs at 10 MHz, 833
ns at 12 MHz, 625 ns at 16 MHz, or 500 ns at 20 MHz.
TABLE 1 Notes (Cont.):
(10)Software programmable (4 options). Includes RT-to-RT Timeout
(measured mid-parity of transmit Command Word to mid-sync of
transmitting RT Status Word).
(11)Measured from mid-parity crossing of Command Word to mid-sync
crossing of RT's Status Word.
(12)External 10 µF tantalum and 0.1 µF capacitors should be located
as close as possible to the voltage input pins/balls.
(13)MIL-STD-1760 requires a 20 Vp-p minimum output on the stub con-
nection.
(14)Current drain and power dissipation specs are preliminary and sub-
ject to change.
(15)Power dissipation is the input power minus the power delivered to
the 1553 fault isolation resistors, the power delivered to the bus ter-
mination resistors, and the copper losses in the transceiver isolation
transformer and the bus coupling transformer. An illustration of
external power dissipation for transformer coupled configuration
(while transmitting) is: 0.14 watts for the active isolation transformer,
0.08 watts for the active bus coupling transformer, 0.45 watts for
each of the two bus isolation resistors and 0.15 watts for each of
the two bus termination resistors.
(16)θJC is measured to bottom of ceramic case.
(17)Assuming the use of isolation transformers with the turns ratios
shown in Figure 16 and in the absence of common mode signal on
the 1553 stub, this equates to a nominal stub voltage of 38 VoltsPK-
to-PK transformer-coupled, or 53 VoltsPK-to-PK direct-coupled.
(18)Assuming the use of isolation transformers with the turns ratios
shown in Figure 16 and in the absence of common mode signal on
the 1553 stub, this equates to a nominal stub voltage of 29.8
VoltsPK-to-PK transformer-coupled, or 38.2 VoltsPK-to-PK direct-cou-
pled."