HI-6121PQMF HOLTIC [Holt Integrated Circuits], HI-6121PQMF Datasheet - Page 65

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

CIRCULAR BUFFER MODE 2, Cont.
Data Block completion is based on number of messages, not Buffer Full or Buffer Empty.
Example is set to successfully transact four 32 data word receive messages, then generate IXEQZ interrupt for host.
The data buffer requires minimal processing by host because message information words are stored separately in MIB.
Time-Tag Word 4
Time-Tag Word 3
Time-Tag Word 2
Time-Tag Word 1
Msg Info Word 4
Msg Info Word 3
Msg Info Word 2
Msg Info Word 1
Increasing
Buffer (MIB)
Information
Address
Memory
Message
Receive Subaddress
Descriptor Block
Figure 18. Circular Buffer Mode 2 Example for a Receive Subaddress
0x0607
0x0606
0x0605
0x0604
0x0603
0x0602
0x0601
0x0600
RAM
Address
Current Address
Start Address
Control Word
MIB Address
for a
HOLT INTEGRATED CIRCUITS
Data Words 2-31
Data Words 2-31
Data Words 2-31
Data Words 2-31
MIB Address = 0x0600
Current Address = 0x0500
Start address = 0x0500
Control Word = 0x8042
Initialized Descriptor Values
Data Word 32
Data Word 32
Data Word 32
Data Word 32
Data Word 1
Data Word 1
Data Word 1
Data Word 1
Data Word
HI-6120, HI-6121
Buffer
65
0x057F
0x0561 - 0x057E
0x0560
0x055F
0x0541 - 0x055E
0x0540
0x053F
0x0521 - 0x053E
0x0520
0x051F
0x0501 - 0x051E
0x0500
RAM
Address
Circular Mode 2, 4 messages, IXEQZ Interrupt
MIB start address in RAM
Buffer current address in RAM
Buffer start address in RAM
Msg Count increments to 4,
full count, data block complete.
Device updates CA to equal
buffer Start Address 0x0500.
Device updates MIBA to equal
MIB Start Address 0x0600.
IXEQZ interrupt is generated.
Msg Count increments to 3.
Device updates CA to 0x0560
and updates MIBA to 0x0606.
Msg Count increments to 2.
Device updates CA to 0x0540
and updates MIBA to 0x0604.
Msg Count increments to 1.
Device updates CA to 0x0520
and updates MIBA to 0x0602.
Receive Message #1
32 Data Words
Receive Message #4
32 Data Words
Receive Message #3
32 Data Words
Receive Message #2
32 Data Words