HI-6121PQMF HOLTIC [Holt Integrated Circuits], HI-6121PQMF Datasheet - Page 46

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

MESSAGE DATA BUFFERS
The host initializes the Descriptor Table entry for each
subaddress or mode command to select one of four data
buffering methods. Briefly summarized here, the options
are explained in full detail in the next section of this data
sheet:
Indexed (Single Buffer) Method.
A predetermined number of messages (N) is transacted
using a single data buffer in shared RAM. Several host
interrupt options are offered, including host interrupt when
all N messages are successfully completed. This method
also supports single-message mode when N is purposely
initialized to zero.
Double (or Ping-Pong) Buffer Method.
Successive messages alternate between two 34-word
data buffers in shared RAM. Several host interrupt options
are offered.
Circular Buffer Mode 1.
Buffer boundaries determine when the bulk transfer is
complete. Message information and time-tag words are
stored in the same buffer with data words. Several host
interrupt options are offered, including host interrupt when
the allocated data buffer is full.
BUFFER
MODE
Indexed
Ping-Pong
Circular 1
Circular 2
Broadcast Data Separation
When the NOTICE2 option is enabled, data words resulting from broadcast receive commands will be stored separately
from data resulting from non-broadcast receive commands when using i
NOTICE2 applies, all subaddresses using indexed or ping-pong modes must have an assigned 34-word broadcast data
buffer in addition to the primary buffers listed above. Broadcast data segregation cannot be done using either circular
buffer mode.
DATA BUFFER(S)
NUMBER & SIZE
one, host defines
size for N messages
two 34-word buffers,
1 message each
one, host defines
size for N words
one, host defines
size for N messages,
plus Msg Info Block
DATA BUFFER MODES AT A GLANCE
MESSAGE
INFO WORDS
stored in same
buffer as data
stored in same
buffers as data
stored in same
buffer as data
stored in
separate buffer
(Msg Info Block)
HOLT INTEGRATED CIRCUITS
HI-6120, HI-6121
46
SUITABLE FOR
MODE CODES?
yes, only single
message mode
yes
no
no
Circular Buffer Mode 2.
The number of messages transacted defines bulk transfer
progress. Message data words are stored contiguously in
one buffer while message information and time-tag words
are stored in a separate buffer. Several host interrupt
options are offered, including host interrupt when all N
messages are completed.
Simplified Mode Command Processing.
This is a global option that applies for all mode code
commands, when enabled. Mode commands have either
one data word, or no data word. Instead of using data
buffers for storing this limited mode command data, the
message data is stored directly within the Descriptor Table.
This option for mode commands is described in the section
called “Mode Command Processing.”
ndexed or ping-pong buffer modes. When
PRIMARY APPLICATION
For transacting N (multiple) messages
with optional host interrupt when done
For transacting single messages,
alternating between A and B buffers
For transacting messages until buffer is
full / empty, optional interrupt when done
For transacting N (multiple) messages
with optional host interrupt when done.
Data buffer holds contiguous pure data.