Datasheet

MAX31782
System Management Microcontroller
11
The memory is implemented using the Harvard archi-
tecture, with separate address spaces for program
and data memory. A pseudo-Von Neumann memory
map is also used placing ROM, application code, and
data memory into a single contiguous memory map.
The pseudo-Von Neumann memory map allows data
memory to be mapped into program space, permitting
code execution from data memory. In addition, program
memory can be mapped into data space, permitting
code constants to be accessed as data memory. Figure
3 shows the device’s memory map when executing from
program memory space. Refer to the MAX31782 User’s
Guide for memory map information when executing from
data or ROM space.
The incorporation of flash memory allows field upgrade
of the firmware. Flash memory is password protected
with a 16-word key, denying access to program memory
by unauthorized individuals.
Utility ROM
The utility ROM is a 4KWord block of internal ROM
memory that defaults to a starting address of 8000h. The
utility ROM consists of subroutines that can be called
from application software. These include the following:
• In-systemprogramming(bootstraploader)overJTAG
or I
2
C-compatible interfaces
• In-circuitdebugroutines
• Callableroutinesforin-applicationflashprogramming
Following any reset, execution begins in the utility ROM.
The ROM software determines whether the program
execution should immediately jump to location 0000h,
the start of application code, or to one of the special
routines mentioned. Routines within the utility ROM are
firmware-accessible and can be called as subroutines
by the application software. More information on the util-
ity ROM contents is contained in the MAX31782 User’s
Guide.
Figure 3. Memory Map
SYSTEM
REGISTERS
PERIPHERAL
REGISTERS
DP
16 x 16
STACK
M5
M4
M3
M2
M1
M0
5h
0Fh
00h
4h
3h
2h
1h
0h
FFFFh FFFFh FFFFh
8FFFh9FFFh8FFFh
7FFFh
001Fh
0010h
0000h
0000h 0000h
4K x 16
UTILITY ROM
8K x 8
UTILITY ROM
4K x 16
UTILITY ROM
2K x 8
SRAM DATA
1K x 16
SRAM DATA
32K x 16
USER PROGRAM
MEMORY
PASSWORD
8000h 8000h 8000h
07FFh 03FFh
DPC
SP
IP
PFX
A
AP
Fh
00h 0Fh
00h 1Fh
Eh
Dh
Ch
Bh
9h
8h
PROGRAM
MEMORY SPACE
DATA MEMORY
(BYTE MODE)
DATA MEMORY
(WORD MODE)