www.pudn.com > IIC.zip > Init.s

;************************************************************************************************ 
;File Name:		Init.s 
;Description:	start up configuare	 
;Author:		weian 
;Date:			2004-3-1 
;*************************STACK DEFINATION******************************************************/	 
AT91C_BASE_CKGR       EQU  0xFFFFFC20       
AT91C_CKGR_MOSCEN     EQU  0x1 
AT91C_CKGR_OSCOUNT    EQU  0x0ff00 
CKGR_MOR              EQU  0xFFFFFC20 
 
AT91_USER_Stack_Begin EQU  0x21000000 
AT91_Stack_Begin      EQU  0x21000000 
 
ARM_MODE_USER         EQU  0x10 
ARM_MODE_FIQ          EQU  0x11 
ARM_MODE_IRQ          EQU  0x12 
ARM_MODE_SVC          EQU  0x13 
ARM_MODE_ABORT        EQU  0x17 
ARM_MODE_UNDEF        EQU  0x1B 
ARM_MODE_SYS          EQU  0x1F 
ARM_MODE_MASK         EQU  0x1F 
 
I_BIT                 EQU  0x80 
F_BIT                 EQU  0x40 
T_BIT                 EQU  0x20 
 
IRQ_STACK_SIZE		  EQU  0x10 
FIQ_STACK_SIZE		  EQU  0x04 
ABT_STACK_SIZE		  EQU  0x04 
UND_STACK_SIZE		  EQU  0x04 
SVC_STACK_SIZE		  EQU  0x10 
USER_STACK_SIZE		  EQU  0x4000 
;*************************REGISTER DEFINATION*****************************************************/ 
AT91C_AIC_IMR              EQU  0xfffff110 
 
 
;*************************************************************************************************/ 
    CODE32 
	AREA    	Init,CODE,READONLY 
	ENTRY  
	b           Reset_Handler 
	 
undefvec        B           undefvec  
 
swivec          B           swivec    
 
pabtvec         B           pabtvec   
 
dabtvec         B           dabtvec   
 
rsvdvec         B           rsvdvec   
 
irqvec          ldr         pc, [pc,#-0xF20]  
 
fiqvec          ldr         pc, [pc,#-0xF20]    
     
 
Reset_Handler 
;********************** 
;Disable All Interrupts 
;********************** 
  ldr r0 ,=0x0 
  ldr r1 ,=AT91C_AIC_IMR 
  str r0,[r1] 
;******************* 
;- The reset handler 
;******************* 
 
 
; Get the CKGR Base Address 
	ldr     r1, = AT91C_BASE_CKGR	 
	 
;-Main oscillator Enable register	APMC_MOR : Enable main oscillator , OSCOUNT = 0xFF 
;	ldr 	r0, = AT91C_CKGR_MOSCEN:OR:AT91C_CKGR_OSCOUNT 
	ldr 	r0, =0x0000FF01 
	str     r0, [r1, #CKGR_MOR] 
 
;************************************** 
;-Low level Init (PMC, AIC, EBI,USART) 
;************************************** 
 
;- Add loop to compensate Main Oscillator startup time 
	ldr 	r0, =0x00000010 
LoopOsc 
	subs    r0, r0, #1               
	bhi     LoopOsc 
	 
	ldr 	r1, = 0x00204000	 
 
;- Set up Supervisor Mode and set SVC Stack 
	msr     cpsr_c, #(ARM_MODE_SVC | I_BIT | F_BIT) 
;Insure word alignement 
	bic     r1, r1, #3                   
; Init stack SYS	 
	mov     sp, r1                       
	IMPORT AT91F_LowLevelInit 
	bl AT91F_LowLevelInit 
	 
;******************************************* 
; Setup the stack for each mode 
;******************************************* 
   ldr		r0, =AT91_Stack_Begin 
 
;Set up Supervisor Mode and set SVC Mode Stack 
	msr     CPSR_c, #(ARM_MODE_SVC | I_BIT | F_BIT) 
;Init stack Sup 
	mov     r13, r0                      
 	sub     r0, r0, #SVC_STACK_SIZE 
 
;Set up Interrupt Mode and set IRQ Mode Stack 
	msr     CPSR_c, #(ARM_MODE_IRQ | I_BIT | F_BIT) 
;Init stack IRQ 
	mov     r13, r0                      
	sub     r0, r0, #IRQ_STACK_SIZE 
  
;Set up Fast Interrupt Mode and set FIQ Mode Stack 
	msr     CPSR_c, #(ARM_MODE_FIQ | I_BIT | F_BIT) 
;Init stack FIQ 
	mov     r13, r0 
	sub     r0, r0, #FIQ_STACK_SIZE 
 
;Set up Abort Mode and set Abort Mode Stack 
	msr     CPSR_c, #(ARM_MODE_ABORT | I_BIT | F_BIT) 
;Init stack Abort 
	mov     r13, r0 
	sub     r0, r0, #ABT_STACK_SIZE 
	 
;Set up Undefined Instruction Mode and set Undef Mode Stack 
	msr     CPSR_c, #(ARM_MODE_UNDEF | I_BIT | F_BIT) 
;Init stack Undef 
	mov     r13, r0  
	sub     r0, r0, #UND_STACK_SIZE 
 
;Set up Sys Mode, set User Mode Stack and enable interrupts   
	msr     CPSR_c, #(ARM_MODE_SYS | F_BIT) 
; Init stack User 
	mov     r13, r0 
;Change to User Mode 
    ;msr     CPSR_c, #ARM_MODE_USER 
     
 
;*****************************************************          
;Jump to Main Routine	 
	  IMPORT   TWI_Test 
      BL       TWI_Test 
here  B  	   here 
 
	  END