hi-6131pqtf QuickLogic Corp, hi-6131pqtf Datasheet - Page 159

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

No mode data word is transmitted. Terminal status is
updated.
Twenty-seven mode codes are considered “reserved” in
MIL-STD-1553B:
Treatment of these reserved mode commands depends
on their respective Illegalization Table entries. As de-
scribed above for undefined mode commands, response
depends on whether or not illegal command detection
applies.
Any mode commands not implemented in the HI-6130/31
terminal should be treated the same as reserved mode
commands. For example, command MC0 (with T/R = 1)
is probably unimplemented because the HI-6130 does
not have provisions for accepting “dynamic bus control”.
The important point is that “illegal command detection”
should be universally applied (or not applied) when set-
ting up a HI-6130/31 Remote Terminal application. Here
are the two options:
Not using Illegal command detection. The HI-6130/31
Illegalization Table is left in its default state (all locations
equal to MR post-reset 0x0000). The terminal responds
“in form” to all valid commands, whether legal or illegal.
Using illegal command detection. The HI-6130/31 Il-
legalization Table is initialized by the host to implement
“illegal command detection”. The host sets bits for all
illegal commands. This generally includes the reserved
and unimplemented mode commands, unimplemented
subaddresses (or specific word counts, T/R bit states,
and/or broadcast vs. non-broadcast status within subad-
dresses). Treatment for the undefined mode commands
depends on UMCINV bit.
The host defines terminal response for all individual
commands by initializing the Descriptor Table, fully de-
scribed later. At this point, a few comments about the
Descriptor Table are appropriate.
The command SA (subaddress) field has a range of 0
to 31 (0x1F). When SA is in the range 1 to 30 (0x1E),
the command is a transmit or receive “subaddress com-
mand”. The number of data words transmitted or re-
ceived is expressed in the low order 5 bits. When SA
equals 0 or 31 (0x1F) the command is a mode com-
mand and the mode code value is expressed in the low
order 5 bits.
For each subaddress, separate table “descriptor blocks”
Mode Codes 9 through 15 with T/R bit = 1
Mode Codes 22 through 31 with T/R bit = 1
Mode Codes 22 through 31 with T/R bit = 0
HOLT INTEGRATED CIRCUITS
HI-6130, HI-6131
159
for transmit and receive commands permit different data
buffering to be applied. The host initializes the table so
each transmit-subaddress and each receive-subad-
dress uses one of four methods for storing message
data. During table initialization, memory is allocated in
shared RAM for storing message data according to the
application requirements. Each transmit-subaddress
and receive-subaddress has one or more data pointers
(depending on buffer method) addressing its reserved
data buffer(s).
Each mode command also has its own table “descrip-
tor block”. Mode commands have either one data word
or no associated data words. Descriptor words used
as data pointers by “subaddress commands” are in-
stead used for direct storage of transacted mode data
words. Mode commands that transmit or receive mode
data words have a dedicated storage address range in
shared RAM, eliminating the need for descriptor table
data pointers.
Each mode command with mode data word has its own
fixed address for data storage. This includes reserved
mode codes with data word. Thus the HI-6130/31 can
respond consistently for all mode commands; transmit-
ted data values for “in form” responses (when “illegal
command detection” is not used) can be predetermined,
even for the reserved mode commands.
19.1.1. RT to RT Commands.
The MIL-STD-1553 standard allows for data word trans-
mission from a specified transmitting terminal to a dif-
ferent receiving terminal. When broadcast commands
are allowed, data transmission can be addressed to
the broadcast terminal address, RT31. If broadcast is
allowed, the host should initialize the BCSTINV (broad-
cast invalid) bit in Configuration Register 1 to logic 0.
All RT to RT commands are characterized by a pair of
contiguous command words: Command Word 1 is a
receive command addressed to the intended receiving
terminal, then Command Word 2 is a transmit command
addressed to a single transmitting terminal. Command
Word 2 cannot be broadcast address RT31. The HI-6130
automatically detects and handles RT to RT commands,
except when either command word contains a subad-
dress field equal to 0x0 or 0x1F. Either subaddress val-
ue indicates a mode code command; the device treats
RT to RT commands with mode code as invalid. If either
RT-RT command word is addressed to the HI-6130/31
terminal but contains subaddress 0x0 or 0x1F, the com-
mand is not recognized; there is no RT command re-
sponse, and no status updating for the benefit of follow-