HI-6121PQMF HOLTIC [Holt Integrated Circuits], HI-6121PQMF Datasheet - Page 51

• Manufacturer Part Number: HI-6121PQMF
• Description: MIL-STD-1553 Remote Terminal ICs
• Manufacturer: HOLTIC [Holt Integrated Circuits]

MESSAGE DATA BUFFERS, Cont.
TRANSMIT MODE COMMAND
MESSAGE INFORMATION WORD
The transmit mode command data structure contains a Message Information Word, a Time-Tag word and may contain one
Data Word. For mode commands with associated data word (mode codes 16-31 decimal) the host is responsible for loading
the Mode Command Data Table before transmit mode commands are received (e.g., Transmit Vector Word mode code). Two
mode codes have internally generated data words: MC18 “Transmit Last Command” and MC19 “Transmit BIT Word”. For
these, the device automatically transmits the data word then copies the transmitted data value to the stored data structure.
Here is an example data structure for a transmit mode command with data (mode code values 0x10 through 0x1F). This
applies to MC16 “Transmit Vector Word”. Notice that the data pointer points to the data structure starting address, not the
mode data word. The data pointer is located in the transmit mode command’s Descriptor Block, fully described later:
Three transmit mode commands with data are not defined under MIL-STD-1553B. These are MC17, MC20 and MC21 (mode
codes 0x11, 0x14 and 0x15 respectively). However the device responds “in form” if illegal command detection is not used
(corresponding bits in Illegalization Table are logic 0)
For mode code commands without data, the data structure contains only the Message Information Word and Time-Tag Word.
Here is an example data structure for a transmit mode command without data (mode code values 0x00 through 0x0F). Again,
the data pointer points to the data structure starting address. The data pointer is located in the transmit mode command’s
Descriptor Block, fully described later:
The following bits comprise the mode transmit Message Information Word:
Bit No.
15-
13
11
10
12
MSB
Data pointer equals 0x0500
Data pointer equals 0x0500
14
15 14 13 12 11 10 9
X
X
Mnemonic Function
----
GAPERR
WCTERR Word Count Error
----
MERR
X
Not used.
Gap Error.
This bit is high when bus activity was detected immediately after the mode command word, when a
gap was expected.
This bit is asserted if command is received with unexpected data word(s).
Not used.
Message Error.
This bit is asserted when message error status change occurs during command processing.
12-13 for details.
8
———
———
———
———
X
7
X
6
Hex Address
Hex Address
>
>
>
>
Data Buffer
Data Buffer
5
0x0500
0x0501
0x0502
0x0500
0x0501
4
HOLT INTEGRATED CIRCUITS
3
2
HI-6120, HI-6121
and
1
0
the UMCINV bit in Configuration Register 1 is logic 0.
Word Description
Message Information Word
Time-Tag Word
Mode Data Word
Word Description
Message Information Word
Time-Tag Word
LSB
51
Word Is Written By
Device, after message completion
Host, prior to terminal’s data transmit
(except MC18, MC19 are written
by the device after completion)
Word Is Written By
Device, after message completion
“
“
“
“
“
“
“
“
See bits