BCRTM-23
5.4 RAM Interface
The BCRTM’s RRD, RWR, and MEMCSO signals serve as
read and write controls during BCRTM memory accesses.
The host subsystem signals RD, WR, and MEMCSI
propagate through the BCRTM to become RRD, RWR, and
MEMCSO outputs to support a pseudo-dual-port. During
BCRTM-RAM data transfers, the host subsystem’s memory
signals are ignored until the BCRTM access is complete.
5.5 Legalization Bus
The BCRTM’s Manchester II encoder/decoder interfaces
directly with the1553 bus transceiver, using the TAO-TAZ
and RAZ-RAO signals for Channel A, and TBO-TBZ and
RBZ-RBO signals for Channel B.
The BCRTM also provides a TIMERON signal output and
an active channel output indicator (CHA/B) to assist in
meeting the MIL-STD-1553B fail-safe timer requirements..
6.0 REMOTE TERMINAL ARCHITECTURE
The Remote Terminal architecture is a descriptor-
based configuration of relevant parameters. It is composed
of an RT Descriptor Space (see figure 5) and internal, host-
programmable registers. The Descriptor Space contains
only descriptors. Descriptors contain programmable
subaddress parameters relating to handling message
transfers. Each descriptor consists of four words: (1) a
Control Word, (2) a Message Status List Pointer, (3) a Data
List Pointer, and (4) an unused fourth word (see figure 6.)
These words indicate how to perform the data transfers
associated with the designated subaddress.
BCRTM
CHANNEL A CHANNEL B
DUAL
TXINHA
TXINHB
CHANNEL A CHANNEL B
TRANSCEIVER
TIMRONB
CHA/B
Figure 4. Dual-Channel Transceiver
#’S 15 & 31
#’S 1 & 17
#’S 0 & 16
- STARTING ADDRESS
INITIALIZED BY CPU
IN THE RT DESCRIPTOR
TRANSMIT
SUBADDRESS
SUBADDRESS
SUBADDRESS
SUBADDRESS
SUBADDRESS
#1
#2
#31
#1
#2
#31SUBADDRESS
MODE CODE
MODE CODE
MODE CODE
RECEIVE
RECEIVE
RECEIVE
UNUSED
TRANSMIT
TRANSMIT
UNUSED
SPACE REGISTER
Figure 5. Descriptor Space
FOR FUTURE EXPANSION
DATA LIST POINTER
MESSAGE STATUS LIST POINTER
INDEX
06815
UNUSED II
10
I I
9 7
ILLEGAL BROADCAST
SUBADDRESS
ILLEGAL
INTERRUPT WHEN
ADDRESSED
INTERRUPT WHEN
INDEX = 0
SUBADDRESS
Figure 6. Remote Terminal Subaddress Descriptor