HI-6120 HOLTIC [Holt Integrated Circuits], HI-6120 Datasheet - Page 72

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

11.1.2. Transmit Subaddress Command
The external host is responsible for organizing the data packet (i.e., storing N data words) in shared RAM and initializ-
ing the applicable data pointer. The host must allocate two memory locations at the starting address of the data record
for device storage of the transmit subaddress Message Information Word and Time-Tag Word.
Here is an example data structure for a 3-word transmit command. Notice that the Data Pointer points to the data
structure starting address, not the first data word. The data pointer is located in the transmit subaddress command’s
Descriptor Block.
The following bits comprise the transmit subaddress Message Information Word.
Data pointer equals 0x0500 → 0x0500
MSB
Bit No.
4-0
7
6
5
15 14 13 12 11 10 9
X
X
Mnemonic
TXRTERR
RTRT
BUSID
WC4:0
X
Function
RT-RT Transmit Remote Terminal Error.
This bit is set when the terminal decodes a valid RT-RT receive command, but one of four
potential errors is detected in the second command word, CW2: (1) CW2 is addressed
to broadcast address RT31. (2) the CW2 T/R bit equals 0, (3) the CW2 subaddress is a
mode command indicator, 00000 or 11111, or (4) CW2 has same non-broadcast terminal
address as receive command word CW1.
The TXRTERR bit is also set when status word received from the transmitting terminal
is invalid (e.g., parity error) or bits 15:11 in the status word reflect the wrong RT address
(does not match CW2).
Remote Terminal to Remote Terminal Transfer.
Assertion of this bit indicates the receive command was an error-free RT-to-RT transfer.
Bus Identification.
If this bit equals zero, message was transacted on Bus A. If bit equals one, it was trans-
acted on Bus B.
Word Count.
This 5-bit field contains the word count extracted from the command word. Zero indicates
32 words.
8
Hex Address
Data Buffer
X
7
0x0501
0x0502
0x0503
0x0504
6
5
HOLT INTEGRATED CIRCUITS
4
HI-6120, HI-6121
3
Word Description
Message Information Word
Time-Tag Word
Data Word 1
Data Word 2
Data Word 3
2
1
0
72
LSB
Word is Written By ...
Device, after message completion
Host, prior to terminal’s data transmit
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