Core1553BRT-EBR Enhanced Bit Rate 1553 Remote Terminal
Memory Address Mapping
Interrupt Vector Extension
The core supports an external memory address mapper
that allows the RT memory allocation to be easily
customized. To use this function, the CMDVAL output
must be latched by the ADDRLAT signal, as shown in
Figure 6. Then the address mapper function can map the
1553EBR command words, data words including mode
code data, and transfer status words to any memory
address.
The core generates a seven-bit interrupt vector that
contains the sub-address and whether it was a transmit
or receive message. Some systems may need to include
whether the message was broadcast, a mode code, or
the actual word count in the interrupt vector. The core
supports an interrupt vector extension function, similar
to the address mapper function using the INTLAT signal,
as shown in Figure 7.
SET
D
L
Q
Q
CMDVAL
CLK 1553
ADDRLAT
CLR
Address
Mapped
Mapper
Function
MEMADDR
MEMOPER
Address
Figure 6 • Memory Address Mapping
SET
CLR
D
Q
CMDVAL
CLK 1553
INTLAT
L
Q
Extended
Interrupt
Vector
Interrupt
Vector
Extender
INTVECT
Figure 7 • Interrupt Vector Extension
12
Advanced v1.1
ACTEL [ Actel Corporation ]
