Functional Overview
Hex
7F0000
Hex
010000
Program
Program
Hex
020000
Hex
030000
Hex
040000
Program
Program
Program
†
†
†
†
†
External
External
External
External
External
7F3FFF
7F4000
013FFF
014000
023FFF
024000
033FFF
034000
043FFF
044000
......
Reserved
Reserved
Reserved
Reserved
Reserved
(OVLY = 1)
(OVLY = 1)
(OVLY = 1)
(OVLY = 1)
(OVLY = 1)
External
(OVLY = 0)
External
(OVLY = 0)
External
(OVLY = 0)
External
(OVLY = 0)
External
(OVLY = 0)
017FFF
018000
027FFF
028000
037FFF
038000
047FFF
048000
7F7FFF
7F8000
On-Chip
ROM
Reserved
External
External
External
Reserved
03DFFF
03E000
03FFFF
01FFFF
7FFFFF
02FFFF
04FFFF
Page 1
XPC=1
Page 2
XPC=2
Page 127
XPC=7Fh
Page 3
XPC=3
Page 4
XPC=4
†
The lower 16K words of pages 1 through 127 are only available when the OVLY bit is cleared to 0. If the OVLY bit is set to 1, the on-chip memory
is mapped to the lower 16K words of all program space pages.
Figure 3−5. 5404 Extended Program Memory Map
3.5.3 Relocatable Interrupt Vector Table
The reset, interrupt, and trap vectors are addressed in program space. These vectors are soft — meaning that
the processor, when taking the trap, loads the program counter (PC) with the trap address and executes the
code at the vector location. Four words, either two 1-word instructions or one 2-word instruction, are reserved
at each vector location to accommodate a delayed branch instruction which allows branching to the
appropriate interrupt service routine without the overhead.
At device reset, the reset, interrupt, and trap vectors are mapped to address FF80h in program space.
However, these vectors can be remapped to the beginning of any 128-word page in program space after
device reset. This is done by loading the interrupt vector pointer (IPTR) bits in the PMST register with the
appropriate 128-word page boundary address. After loading IPTR, any user interrupt or trap vector is mapped
to the new 128-word page.
NOTE: The hardware reset (RS) vector cannot be remapped because the hardware reset loads the IPTR
with 1s. Therefore, the reset vector is always fetched at location FF80h in program space.
28
SPRS007D
November 2001 − Revised April 2004
TI [ TEXAS INSTRUMENTS ]
