Rainbow Electronics MAXQ2010 - Manual (Page 22)

MAXQ2010
16-Bit Mixed-Signal Microcontroller with LCD
22 ______________________________________________________________________________________
On reset, the stack pointer, SP, initializes to the top of
the stack (0Fh). The CALL, PUSH, and interrupt-vector-
ing operations increment SP, then store a value at the
location pointed to by SP. The RET, RETI, POP, and
POPI operations retrieve the value at SP and then
decrement SP.
Utility ROM
The utility ROM is a 4KB 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) using
JTAG interface
• In-circuit debug routines
• Test routines (internal memory tests, memory loader,
etc.)
• User-callable routines for in-application flash pro-
gramming and fast table lookup
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 user-application code, or to one of the spe-
cial routines mentioned. Routines within the utility ROM
are user-accessible and can be called as subroutines
by the application software. More information on the
utility ROM contents is contained in the
MAXQ Family
User’s Guide: MAXQ2010 Supplement .
Some applications require protection against unautho-
rized viewing of program code memory. For these
PROGRAM
SPACE
DATA
SPACE
2K x 16
UTILITY ROM
1K x 16
DATA RAM
32K x 16
PROGRAM
MEMORY
8000h
00h
0Fh
FFFFh WBSn = 1
FFFFh
WBSn = 0
FFFFh
07FFh 03FFh
0000h 0000h
87FFh
7FFFh
0000h
0Fh
07h
06h
00h
1Fh
SPRs
SFRs
REGISTERS FFh
16 x 16
STACK
Figure 5. MAXQ2010 Default Memory Map