NXP Semiconductors LPC24XX UM10237 User Manual

Page 754

UM10237_4

User manual

Rev. 04 — 26 August 2009

754 of 792

NXP Semiconductors

UM10237

Chapter 35: LPC24XX RealMonitor

NOP ; Insert User code valid signature here.

LDR pc, [pc, #-0x120] ;Load IRQ vector from VIC

LDR PC, FIQ_Address

Reset_Address

DCD __init

;Reset Entry point

Undefined_Address

DCD rm_undef_handler ;Provided by RealMonitor

SWI_Address

DCD 0

;User can put address of SWI handler here

Prefetch_Address

DCD rm_prefetchabort_handler

;Provided by RealMonitor

Abort_Address

DCD rm_dataabort_handler

;Provided by RealMonitor

FIQ_Address

DCD 0

;User can put address of FIQ handler here

AREA init_code, CODE

ram_end EQU 0x4000xxxx ; Top of on-chip RAM.

__init

; /*********************************************************************

; * Set up the stack pointers for various processor modes. Stack grows

; * downwards.

; *********************************************************************/

LDR r2, =ram_end ;Get top of RAM

MRS r0, CPSR ;Save current processor mode

; Initialize the Undef mode stack for RealMonitor use

BIC r1, r0, #0x1f

ORR r1, r1, #0x1b

MSR CPSR_c,

;Keep top 32 bytes for flash programming routines.

;Refer to Flash Memory System and Programming chapter

SUB sp,r2,#0x1F

; Initialize the Abort mode stack for RealMonitor

BIC r1, r0, #0x1f

ORR r1, r1, #0x17

MSR CPSR_c,

;Keep 64 bytes for Undef mode stack

SUB sp,r2,#0x5F

; Initialize the IRQ mode stack for RealMonitor and User

BIC r1, r0, #0x1f

ORR r1, r1, #0x12

MSR CPSR_c,

;Keep 32 bytes for Abort mode stack

SUB sp,r2,#0x7F

; Return to the original mode.

MSR CPSR_c,

; Initialize the stack for user application

; Keep 256 bytes for IRQ mode stack

SUB sp,r2,#0x17F