HI-6120 HOLTIC [Holt Integrated Circuits], HI-6120 Datasheet - Page 26

• Manufacturer Part Number: HI-6120
• Description: MIL-STD-1553 Remote Terminal ICs
• Manufacturer: HOLTIC [Holt Integrated Circuits]

Bit No.
9
Mnemonic
MCOPT4
(continued)
R/W Reset Function
R/W
0
The “selected transmitter shutdown” (MC20 decimal) and “override selected
transmitter shutdown” (MC21 decimal) mode commands act similarly to MC4
and MC5 respectively, except bus shutdown (or shutdown override) is condi-
tional, based on the value of a mode data word received with the command.
To act on a given bus, the received mode data word must match a predeter-
mined “bus select” value. Bus shutdown (or shutdown override) can only act
on the inactive bus, and only when the received mode data word matches
the “bus select” value for that bus. When a MC20 mode data word matches
the “bus select” value for the inactive bus, the terminal fulfills shutdown for
the inactive bus, disabling the transmitter and receiver, or transmitter only,
depending on the state of the SDSEL bit in Configuration Register 1. The de-
vice affirms shutdown status by updating bits 15-12 in the BIT Word Register.
When a MC21 mode data word matches the “bus select” value for the inac-
tive bus, the terminal fulfills shutdown override for the inactive bus, enabling
the transmitter (and receiver, if the SDSEL bit in Configuration Register 1 is
logic 0). The device affirms override status by resetting bits 15-12 in the BIT
Word Register.
When the MCOPT4 bit equals zero, unique “bus select” values should be ini-
tialized by the host in the “Bus A Select” register (0x0012) and “Bus B Select”
register (0x0013) for fulfillment of “selected transmitter” shutdown and over-
ride mode commands. When MCOPT4 equals zero, transmitter shutdown (or
shutdown override) automatically occurs when the received mode data value
matches the inactive bus “Bus Select” register.
Below shows device response for “transmitter shutdown” and “override trans-
mitter shutdown” mode code commands for different option configurations:
MC20 (or MC21)
MC20 (or MC21)
does NOT match
MC4 (or MC5)
value matches
unconditional
if mode data
“Bus Select”
if mode data
“Bus Select”
fulfillment
HOLT INTEGRATED CIRCUITS
value
value
The MCOPT4 bit in Configuration Register 2 is logic 0 or 1
HI-6120, HI-6121
The MCOPT4 bit in Configuration Register 2 is logic 0
26
Inactive Bus Tx & Rx
Inactive Bus Tx & Rx
Inactive Bus Tx & Rx
if the SDSEL config.
if the SDSEL config.
Disabled (Enabled).
(only Tx is disabled,
Disabled (Enabled).
(only Tx is disabled,
status not changed
bit = 1)
bit = 1)
Status Word
Status Word
Status Word
transmitted,
transmitted,
transmitted,
broadcast
broadcast
broadcast
unless
unless
unless
RXSD bits updated.
RXSD bits updated.
Register, TXSD &
SDSEL config. bit
Register, TXSD &
SDSEL config. bit
& RXSD bits are
Register, TXSD
(only TXSD bit
(only TXSD bit
updated, if the
updated, if the
In BIT Word
In BIT Word
In BIT Word
static
= 1)
= 1)