hi-6131pqtf QuickLogic Corp, hi-6131pqtf Datasheet - Page 182

• Manufacturer Part Number: hi-6131pqtf
• Description: Mil-std-1553 / Mil-std-1760 3.3v Bc / Mt / Rt Multi-terminal Device
• Manufacturer: QuickLogic Corp

20. REMOTE TERMINAL RT1 AND
The memory structures described up to this point com-
prise not more than 1K words of the lower memory ad-
dress space. The remaining memory is allocated by the
host for message data storage, to fulfill application re-
quirements. This section describes the remaining data
structures in shared RAM that control (and result from)
command processing.
By initializing the Descriptor Table, the host allocates
memory space for storing data for each subaddress used
in the Remote Terminal application. Each legal Receive
Subaddress and each legal Transmit Subaddress are
usually assigned unique buffer memory spaces. (Excep-
tion: To comply with the requirements for MIL-STD-1553
data wrap-around, it is convenient to assign the data
wrap-around subaddress to use the same buffer space
for both receive and transmit commands.)
As an option, data from broadcast receive commands
can be stored separately from data resulting from non-
broadcast receive commands. Each subaddress buffer
can use any of four data storage methods offered.
Subaddress (non-mode) commands are transacted with
one to 32 data words. These are stored in a data buffer in
shared RAM. For receive commands, the device stores
data received during message processing in the shared
RAM buffer. Later, the host retrieves these data words
from the buffer. In the case of transmit commands, the
host has previously stored transmit data words in the
transmit subaddress buffer. The device retrieves these
data words for transmission while processing the trans-
mit command.
For each complete message processed, the message
data stored in the buffer is comprised of these elements:
1. Message Information Word.
2. Time-Tag Word.
3. One to 32 Data Words transmitted or received dur-
The Message Information word and Time-Tag word are
generated by the device and stored in assigned buffer
space to aid the host in further message processing.
The Message Information word contains message type,
word count and message error information. The 16-bit
Time-Tag word contains the value in the device internal
Time-Tag counter when the command is validated.
The host initializes the Descriptor Table entry for each
subaddress or mode command to select one of four data
ing message transaction ( except no data word for
mode code commands 0 - 15 decimal).
RT2 MESSAGE DATA BUFFERS
HOLT INTEGRATED CIRCUITS
HI-6130, HI-6131
182
buffering methods.
1. Indexed (Single Buffer) Method (see 20.4).
2. Double (or Ping-Pong) Buffer Method (see 20.3).
3. Circular Buffer Mode 1 (see 20.5).
4. Circular Buffer Mode 2 (see 20.6).
The data buffer options are summarized in Table 15.
Simplified Mode Command Processing.
This is a global option that applies for all mode code
commands, when enabled. Mode commands have ei-
ther 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.”
Broadcast Data Separation
When the NOTICE2 option is enabled, data words re-
sulting from broadcast receive commands will be stored
separately from data resulting from non-broadcast re-
ceive commands when using indexed or ping-pong buf-
fer modes. When NOTICE2 applies, all subaddresses
using indexed or ping-pong modes must have an as-
signed 34-word broadcast data buffer in addition to the
primary buffers listed above. Broadcast data segrega-
tion cannot be done using either circular buffer mode.
A predetermined number of messages (N) is trans-
acted 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-mes-
sage mode when N is purposely initialized to zero.
Successive messages alternate between two 34-
word data buffers in shared RAM. Several host in-
terrupt options are offered.
Buffer boundaries determine when the bulk trans-
fer 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.
The number of messages transacted defines bulk
transfer progress. Message data words are stored
contiguously in one buffer while message informa-
tion 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.