5962G8957701ZA View Datasheet(PDF) - Aeroflex UTMC

Part Name

Description

Manufacturer

5962G8957701ZA

BCRTM

Aeroflex UTMC 

BIT 8

BITs 7-0

Monitor RT-RT Transfer. Set by the CPU, this function indicates that the BCRTM should receive and store

the message beginning at the location indicated by the data pointer.

Time Delay. The CPU sets this field, which causes the BCRTM to delay the specified time between sequential

message starts (see figures 13 and 14). Regardless of the value in the Time Delay field (including zero), the

BCRTM will at least meet the minimum 4µs intermessage gap time as specified in MIL-STD-1553B. The

timer is enabled by having a non-zero value in this bit field. When using this function, please note:

• Timer resolution is 16µs. As an example, if a given message requires 116µs to complete (including the minimum

4ms intermessage gap time) the value in the Time Delay field must be at least 00001000

(8 x 16µs = 128µs) to provide an intermessage gap greater than the 4ms minimum requirement.

• If the timer is enabled and the Skip bit is set, the timer provides the programmed delay before proceeding.

• If the message duration exceeds the timer delay, the message is completed just as if the time were

not enabled.

• If SKIP = 1 and EOL = 1 the HPINT is generated if enabled

• If SKIP = 1 and Interrupt and Continue = 1, the STDINT is generated

C. Command Word One. Initialized by the CPU, this location contains the first command word corresponding to the

Command Block’s message transfer.

D. Command Word Two. Initialized by the CPU, this location is for the second (transmit) command word in RT-RT

transfers. In messages involving only one RT, the location is unused.

E. Data Pointer. Initialized by the CPU, this location contains the starting location in RAM for the command block’s

message (see figure 15).

F. Status Word One. Stored by the BCRTM, this location contains the entire Remote Terminal status response.

G. Status Word Two. Stored by the BCRTM, this location contains the receiving Remote Terminal status word. For

transfers involving one Remote Terminal, the location is unused.

H. Tail Pointer. Initialized by the host CPU, the Tail Pointer contains the next Command Block’s starting address.

COMMAND BLOCK #1

DATA POINTER

MESSAGE #1

RAM

DATA WORD #1

DATA WORD #2

Compare Register contents. Program the PCR by setting the

PCR bits corresponding to the RT’s 1553 status word bits

to be compared. If they match (i.e., two 1’s in the same bit

position) then, if enabled in both the BC Command Block

Control Word and in the Standard Interrupt Enable Register

(Register 9), a polling comparison interrupt is generated.

COMMAND BLOCK #2

MESSAGE #2

DATA POINTER

DATA WORD #3

DATA WORD #1

DATA WORD #2

DATA WORD #3

DATA WORD #4

Example 1. No bit match is present

PCR

00000000001

RT’s 1553 Status Word response 00000100010

Result

No Polling Comparison Interrupt

Example 2. Bit match is present

PCR

00100100000

RT’s 1553 Status Word response 00000100000

Result

Polling Comparison Interrupt

Figure 15. Contiguous Data Storage

7.2 Polling

During a typical polling scenario (see figure 16) the Bus

Controller interrogates remote terminals by requesting them

to transmit their status words. This feature can also alert the

host if a bit is set in any RT status word response during

normal message transactions. The BCRTM enables the host

to initialize a chain of Command Blocks with the command

word’s Polling Enable bit. A programmable Polling

Compare Register (PCR) is provided. In the polling mode,

the Remote Terminal response is compared to the Polling

7.3 BC Error Detection

The Bus Controller checks for errors (see the Exception

Handling and Interrupt Logging and the RT Error Detection

sectons, pages 37 and 28) on each message transaction. In

addition, the BC compares the RT command word addresses

to the incoming status word addresses. The BC monitors for

response time-out and checks data and control words for

proper format according to MIL-STD-1553. Illogical

commands include incorrectly formatted RT-RT

Command Blocks.

BCRTM-31

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