hi-6131pqtf QuickLogic Corp, hi-6131pqtf Datasheet - Page 79

• Manufacturer Part Number: hi-6131pqtf
• Description: Mil-std-1553 / Mil-std-1760 3.3v Bc / Mt / Rt Multi-terminal Device
• Manufacturer: QuickLogic Corp

Bit No.
1
0
Mnemonic
BCGCE
BCRME
R/W
R/W
R/W
Reset
0
0
HOLT INTEGRATED CIRCUITS
Function
BC Gap Check Enable.
When this bit is logic 1, the BC verifies that any transmission by a
Remote Terminal on the bus is preceded by an inter-word gap of at
least 4µs. When this minimum gap time is violated, the BC declares
the RT Status Word invalid, and the No Gap error bit is set in the Block
Status Word. Gap detection measures the time span from mid-parity of
last received word, to mid-sync of the following word (defined here as
detection of a properly encoded sync plus two bits). Measured gap time
is adjusted to evaluate just the interval of interest, corresponding to a
bus “dead time” (end-of-parity to start-of-sync) of 2µs minimum.
When this bit is logic 0 (strongly recommended) the BC does not
check for minimum bus “dead time” prior to start of transmission by a
device on the MIL-STD-1553 bus.
BCR Mask Enable.
This bit selects the function of BC Control Word bit 5, Mask Broadcast,
when evaluating the BCR (Broadcast Command Received) bit in RT
status words.
If BCR Mask Enable bit 0 is logic 1, then RT status word BCR bit
masking is enabled. The state of the Mask BCR bit in each BC Control
Word selectively allows or disallows BCR status testing by the BC:
If BCR Mask Enable bit 0 is logic 0, the “Mask BCR” bit in a
message’s BC Control Word indicates the expected state of the BCR bit
in the received RT status word. In this situation, whenever the BCR bit
in the received RT status word differs from the state of the “Mask BCR”
bit in the BC Control Word, a “Status Set” condition occurs and the BC
generates a Status Set interrupt, if enabled.
Table 7 summarizes the effects of BC configuration, message Control
Word and RT Status Word on “Status Set” bit in the Block Status Word.
•
•
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HI-6130, HI-6131
When “Mask BCR” is logic 1 in a message’s BC Control Word (dis-
abling BCR status bit test), the value of the RT status word BCR bit
is “don’t care” in terms of affecting the occurrence of a “Status Set”
condition.
When “Mask BCR” is logic 0 in the message’s BC Control Word,
“Status Set” occurs when the BCR bit in the received RT Status
Word is logic 1.
While broadcast commands never result in transmitted RT status,
the “Mask BCR” bit should be set in BC Control Words for “transmit
status” or “transmit last command” mode commands immediately
following broadcast messages. Setting the “Mask BCR” bit of the
message’s BC Control Word to logic 1 indicates the expected value
of the BCR bit in the received RT Status Word.
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