Actel Core1553, User Manual, Page: 26 / 38

Core1553BRM Demonstration Design
2 6
Interpreting Interrupt Status Messages
The meaning of each of the first four interrupt messages is given below:
2.80E4.0400.4A00
• 2.80e4: IAW = RT SA25 RX
• 0400: IIW = Sub address accessed
• 4A00 : 9 words bus A
• 1.0018: IAW = BC MSG Block 3
• 0002: IIW = CBA interrupt
2.8008.0400.4A00
• 2.8008: IAW = RT SA 2 RX
• 0400: IIW = Sub address accessed
• 4A00: 9 words bus A
2.8004.0400.1200
• 2.8004: IAW = RT SA1 RX
• 0400: IIW = Sub address accessed
• 1200: 2 words bus A
This pattern repeats, with the word count increasing on the third message. Refer to the Interrupts
section of the Core1553BRM Handbook for more information.
Subaddresses
Subaddressing enables designers to create custom bus control or system functions within MIL-STD-
1553B standard. The Core1553BRM demonstration design makes use of custom subaddresses to
control the operation of the remote terminal (
Table 2-4 ).
Table 2-4 • Core1553BRM Demonstration Design Subaddressing
Subaddress Function
25 RT receive disabled. RT sends data.
26 RT transmit disabled. Received data sent to the UART.
27 Both RT receive and transmit disabled
30 Loopback subaddress