CT2553-PCB Aeroflex Circuit Technology, CT2553-PCB Datasheet - Page 13

• Manufacturer Part Number: CT2553-PCB
• Description: Advanced Integrated Mux Aim Hybrid For Mil-std-1553 / Sae-as15531 In Pcb Style
• Manufacturer: Aeroflex Circuit Technology

BC OPERATION
Initialization of the CT2553-PCB via a Reset or by
setting the appropriate Configuration Register bits will
result in placing the CT2553-PCB in the BC operating
mode.
BC MEMORY CONFIGURATION.
configures the memory by: (1) writing the start address of
the Descriptor Stack into the Current Area Stack Point
location; (2) loading the fourth word of each Descriptor
Stack Entry (DSE) with the start location of each
message block; and (3) loading the Message Counter
with the total number of messages to be transmitted. Note
that the Message Count must be written in 1's
compliment. For example, to transmit one message, load
00
If both map areas A and B are utilized, this procedure
must be performed for each area. Note that the Stack
Pointer and Message Counter locations are fixed;
Message Block locations are user-defined.
Each message block must be proceeded by a BC Control
Word (See Figure 14). This word informs the
CT2553-PCB as to the format of the message transfer. Bit
1 of the Control Word defines whether the following
message to RT 31 is to be issued in Broadcast Mode or
whether RT 31 is a unique terminal. Memory locations
must be reserved at the end of each message for: (1) a
Loop Back Word; (2) RTU Status Word(s); and (3)
received Data words. See Figure 16, BC Message
Formats.
Message blocks may be loaded anywhere in the non-fixed
area of the shared RAM. However, each data block may
not cross a 256 word boundary (i.e., bit 8 of the starting
address of the message block must match bit 8 of the
address of the last word of the message block).
FE(H) (See Table 3, BC Memory Map).
0100
0101
0104
0105
0108-013F
0140-017F
0180-01BF
01C0-01FF
0F00-0FFF
0000-00FF
SCDCT2553PCB Rev A Preliminary 7/13/06
TABLE 3 - TYPICAL BC MEMORY MAP
HEX ADDRESS
•
•
User Defined Areas
Fixed Areas
Stack Pointer A
Message Count A
Stack Pointer B
Message Count B
Not Used
Data Block 1
Data Block 2
Data Block 3
Descriptor Stack A
Descriptor Stack B
•
•
FUNCTION
The
user
13
ADDITIONAL FEATURES.
Register – STOP ON ERROR bit can be set. This causes
the CT2553-PCB to halt operation at the end of the
current message transfer if an error is detected. In
addition, setting the Interrupt Mask Register bits will
result in a low pulse on the Interrupt (
occurrence of the respective error, end of message or end
of message frame condition (See Configuration Register
and Interrupt Register sections).
BC TRANSFER-START SEQUENCE
After setting the CONTROLLER START bit in the
Start/Reset Register, the CT2553-PCB takes the
following actions:
Upon completion of the MIL-STD-1553 message
transfer, the CT2553-PCB:
If an error occurs and Stop On Error has been enabled,
the CT2553-PCB stops initiating BC Transfer-Start
sequences. The Stack Pointer will point to the next
message to be transferred (See Figure 17).
1. Reads the Current Area Stack Pointer for the
2. Stores an SOM (Start of Message) flag in the
3. Writes the Time Tag value into the Descriptor
4. Reads the Data Block Address from the fourth
5. Starts the MIL-STD-1553 message transfer.
1. Generates an End Of Message (EOM) or Error
2. Reads the Stack Pointer for the address of the
3. Updates the Block Status Word; resets SOM,
4. Writes the Time Tag value into the Descriptor
5. Increment Pointers: Stack Pointer incremented
6. If more messages remain to be sent, a BC End
address of the Descriptor Stack Entry (DSE).
Block Status word to indicate a transfer
operation in progress.
Stack (See Time Tag).
location of the DSE.
(if applicable) interrupt if enabled.
DSE.
sets EOM, and sets any applicable Error bits.
Stack (See Time Tag).
by 4 and Message Count incremented by 1.
Of Message (BCEOM) interrupt occurs (if
enabled).
The
INT
) pin with each
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Configuration