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thewisenerd/SAM7.S

Last active October 29, 2015 12:06
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SAM7.S
;/*****************************************************************************/
;/* SAM7.S: Startup file for Atmel AT91SAM7 device series */
;/*****************************************************************************/
;/* <<< Use Configuration Wizard in Context Menu >>> */
;/*****************************************************************************/
;/* This file is part of the uVision/ARM development tools. */
;/* Copyright (c) 2005-2006 Keil Software. All rights reserved. */
;/* This software may only be used under the terms of a valid, current, */
;/* end user licence from KEIL for a compatible version of KEIL software */
;/* development tools. Nothing else gives you the right to use this software. */
;/*****************************************************************************/
;/*
; * The SAM7.S code is executed after CPU Reset. This file may be
; * translated with the following SET symbols. In uVision these SET
; * symbols are entered under Options - ASM - Define.
; *
; * REMAP: when set the startup code remaps exception vectors from
; * on-chip RAM to address 0.
; *
; * RAM_INTVEC: when set the startup code copies exception vectors
; * from on-chip Flash to on-chip RAM.
; */
; Standard definitions of Mode bits and Interrupt (I & F) flags in PSRs
Mode_USR EQU 0x10
Mode_FIQ EQU 0x11
Mode_IRQ EQU 0x12
Mode_SVC EQU 0x13
Mode_ABT EQU 0x17
Mode_UND EQU 0x1B
Mode_SYS EQU 0x1F
I_Bit EQU 0x80 ; when I bit is set, IRQ is disabled
F_Bit EQU 0x40 ; when F bit is set, FIQ is disabled
; Internal Memory Base Addresses
FLASH_BASE EQU 0x00100000
RAM_BASE EQU 0x00200000
;// <h> Stack Configuration (Stack Sizes in Bytes)
;// <o0> Undefined Mode <0x0-0xFFFFFFFF:8>
;// <o1> Supervisor Mode <0x0-0xFFFFFFFF:8>
;// <o2> Abort Mode <0x0-0xFFFFFFFF:8>
;// <o3> Fast Interrupt Mode <0x0-0xFFFFFFFF:8>
;// <o4> Interrupt Mode <0x0-0xFFFFFFFF:8>
;// <o5> User/System Mode <0x0-0xFFFFFFFF:8>
;// </h>
UND_Stack_Size EQU 0x00000000
SVC_Stack_Size EQU 0x00000100
ABT_Stack_Size EQU 0x00000000
FIQ_Stack_Size EQU 0x00000000
IRQ_Stack_Size EQU 0x00000080
USR_Stack_Size EQU 0x00000400
ISR_Stack_Size EQU (UND_Stack_Size + SVC_Stack_Size + ABT_Stack_Size + \
FIQ_Stack_Size + IRQ_Stack_Size)
AREA STACK, NOINIT, READWRITE, ALIGN=3
Stack_Mem SPACE USR_Stack_Size
__initial_sp SPACE ISR_Stack_Size
Stack_Top
;// <h> Heap Configuration
;// <o> Heap Size (in Bytes) <0x0-0xFFFFFFFF>
;// </h>
Heap_Size EQU 0x00000000
AREA HEAP, NOINIT, READWRITE, ALIGN=3
__heap_base
Heap_Mem SPACE Heap_Size
__heap_limit
; Reset Controller (RSTC) definitions
RSTC_BASE EQU 0xFFFFFD00 ; RSTC Base Address
RSTC_MR EQU 0x08 ; RSTC_MR Offset
;/*
;// <e> Reset Controller (RSTC)
;// <o1.0> URSTEN: User Reset Enable
;// <i> Enables NRST Pin to generate Reset
;// <o1.8..11> ERSTL: External Reset Length <0-15>
;// <i> External Reset Time in 2^(ERSTL+1) Slow Clock Cycles
;// </e>
;*/
RSTC_SETUP EQU 1
RSTC_MR_Val EQU 0xA5000401
; Embedded Flash Controller (EFC) definitions
EFC_BASE EQU 0xFFFFFF00 ; EFC Base Address
EFC0_FMR EQU 0x60 ; EFC0_FMR Offset
EFC1_FMR EQU 0x70 ; EFC1_FMR Offset
;// <e> Embedded Flash Controller 0 (EFC0)
;// <o1.16..23> FMCN: Flash Microsecond Cycle Number <0-255>
;// <i> Number of Master Clock Cycles in 1us
;// <o1.8..9> FWS: Flash Wait State
;// <0=> Read: 1 cycle / Write: 2 cycles
;// <1=> Read: 2 cycle / Write: 3 cycles
;// <2=> Read: 3 cycle / Write: 4 cycles
;// <3=> Read: 4 cycle / Write: 4 cycles
;// </e>
EFC0_SETUP EQU 1
EFC0_FMR_Val EQU 0x00320100
;// <e> Embedded Flash Controller 1 (EFC1)
;// <o1.16..23> FMCN: Flash Microsecond Cycle Number <0-255>
;// <i> Number of Master Clock Cycles in 1us
;// <o1.8..9> FWS: Flash Wait State
;// <0=> Read: 1 cycle / Write: 2 cycles
;// <1=> Read: 2 cycle / Write: 3 cycles
;// <2=> Read: 3 cycle / Write: 4 cycles
;// <3=> Read: 4 cycle / Write: 4 cycles
;// </e>
EFC1_SETUP EQU 1
EFC1_FMR_Val EQU 0x00320100
; Watchdog Timer (WDT) definitions
WDT_BASE EQU 0xFFFFFD40 ; WDT Base Address
WDT_MR EQU 0x04 ; WDT_MR Offset
;// <e> Watchdog Timer (WDT)
;// <o1.0..11> WDV: Watchdog Counter Value <0-4095>
;// <o1.16..27> WDD: Watchdog Delta Value <0-4095>
;// <o1.12> WDFIEN: Watchdog Fault Interrupt Enable
;// <o1.13> WDRSTEN: Watchdog Reset Enable
;// <o1.14> WDRPROC: Watchdog Reset Processor
;// <o1.28> WDDBGHLT: Watchdog Debug Halt
;// <o1.29> WDIDLEHLT: Watchdog Idle Halt
;// <o1.15> WDDIS: Watchdog Disable
;// </e>
WDT_SETUP EQU 1
WDT_MR_Val EQU 0x00008000
; Power Mangement Controller (PMC) definitions
PMC_BASE EQU 0xFFFFFC00 ; PMC Base Address
PMC_MOR EQU 0x20 ; PMC_MOR Offset
PMC_MCFR EQU 0x24 ; PMC_MCFR Offset
PMC_PLLR EQU 0x2C ; PMC_PLLR Offset
PMC_MCKR EQU 0x30 ; PMC_MCKR Offset
PMC_SR EQU 0x68 ; PMC_SR Offset
PMC_MOSCEN EQU (1<<0) ; Main Oscillator Enable
PMC_OSCBYPASS EQU (1<<1) ; Main Oscillator Bypass
PMC_OSCOUNT EQU (0xFF<<8) ; Main OScillator Start-up Time
PMC_DIV EQU (0xFF<<0) ; PLL Divider
PMC_PLLCOUNT EQU (0x3F<<8) ; PLL Lock Counter
PMC_OUT EQU (0x03<<14) ; PLL Clock Frequency Range
PMC_MUL EQU (0x7FF<<16) ; PLL Multiplier
PMC_USBDIV EQU (0x03<<28) ; USB Clock Divider
PMC_CSS EQU (3<<0) ; Clock Source Selection
PMC_PRES EQU (7<<2) ; Prescaler Selection
PMC_MOSCS EQU (1<<0) ; Main Oscillator Stable
PMC_LOCK EQU (1<<2) ; PLL Lock Status
PMC_MCKRDY EQU (1<<3) ; Master Clock Status
;// <e> Power Mangement Controller (PMC)
;// <h> Main Oscillator
;// <o1.0> MOSCEN: Main Oscillator Enable
;// <o1.1> OSCBYPASS: Oscillator Bypass
;// <o1.8..15> OSCCOUNT: Main Oscillator Startup Time <0-255>
;// </h>
;// <h> Phase Locked Loop (PLL)
;// <o2.0..7> DIV: PLL Divider <0-255>
;// <o2.16..26> MUL: PLL Multiplier <0-2047>
;// <i> PLL Output is multiplied by MUL+1
;// <o2.14..15> OUT: PLL Clock Frequency Range
;// <0=> 80..160MHz <1=> Reserved
;// <2=> 150..220MHz <3=> Reserved
;// <o2.8..13> PLLCOUNT: PLL Lock Counter <0-63>
;// <o2.28..29> USBDIV: USB Clock Divider
;// <0=> None <1=> 2 <2=> 4 <3=> Reserved
;// </h>
;// <o3.0..1> CSS: Clock Source Selection
;// <0=> Slow Clock
;// <1=> Main Clock
;// <2=> Reserved
;// <3=> PLL Clock
;// <o3.2..4> PRES: Prescaler
;// <0=> None
;// <1=> Clock / 2 <2=> Clock / 4
;// <3=> Clock / 8 <4=> Clock / 16
;// <5=> Clock / 32 <6=> Clock / 64
;// <7=> Reserved
;// </e>
PMC_SETUP EQU 1
PMC_MOR_Val EQU 0x00000601
PMC_PLLR_Val EQU 0x00191C05
PMC_MCKR_Val EQU 0x00000007
PRESERVE8
; Area Definition and Entry Point
; Startup Code must be linked first at Address at which it expects to run.
AREA RESET, CODE, READONLY
ARM
; Exception Vectors
; Mapped to Address 0.
; Absolute addressing mode must be used.
; Dummy Handlers are implemented as infinite loops which can be modified.
Vectors LDR PC,Reset_Addr
LDR PC,Undef_Addr
LDR PC,SWI_Addr
LDR PC,PAbt_Addr
LDR PC,DAbt_Addr
NOP ; Reserved Vector
; LDR PC,IRQ_Addr
IRQ_Handler B irqhandler
; LDR PC,FIQ_Addr
LDR PC,[PC,#-0xF20] ; Vector From AIC_FVR
Reset_Addr DCD Reset_Handler
Undef_Addr DCD Undef_Handler
SWI_Addr DCD SWI_Handler
PAbt_Addr DCD PAbt_Handler
DAbt_Addr DCD DAbt_Handler
DCD 0 ; Reserved Address
FIQ_Addr DCD FIQ_Handler
Undef_Handler B Undef_Handler
SWI_Handler B SWI_Handler
PAbt_Handler B PAbt_Handler
DAbt_Handler B DAbt_Handler
FIQ_Handler B FIQ_Handler
AT91C_BASE_AIC EQU 0xFFFFF000
AIC_IVR EQU 0x100
AIC_EOICR EQU 0x130
irqhandler
; Save interrupt context on the stack to allow nesting */
SUB lr, lr, #4
STMFD sp!, {lr}
MRS lr, SPSR
STMFD sp!, {r0,r1,lr}
; Write in the IVR to support Protect Mode */
LDR lr, =AT91C_BASE_AIC
LDR r0, [r14, #AIC_IVR]
STR lr, [r14, #AIC_IVR]
; Branch to interrupt handler in Supervisor mode */
MSR CPSR_c, #Mode_SVC
STMFD sp!, {r1-r4, r12, lr}
MOV lr, pc
BX r0
LDMIA sp!, {r1-r4, r12, lr}
MSR CPSR_c, #Mode_IRQ:OR:I_Bit
; Acknowledge interrupt */
LDR lr, =AT91C_BASE_AIC
STR lr, [r14, #AIC_EOICR]
; Restore interrupt context and branch back to calling code
LDMIA sp!, {r0,r1,lr}
MSR SPSR_cxsf, lr
LDMIA sp!, {pc}^
; irqhandler (end)
; Reset Handler
EXPORT Reset_Handler
Reset_Handler
; Setup RSTC
IF RSTC_SETUP != 0
LDR R0, =RSTC_BASE
LDR R1, =RSTC_MR_Val
STR R1, [R0, #RSTC_MR]
ENDIF
; Setup EFC0
IF EFC0_SETUP != 0
LDR R0, =EFC_BASE
LDR R1, =EFC0_FMR_Val
STR R1, [R0, #EFC0_FMR]
ENDIF
; Setup EFC1
IF EFC1_SETUP != 0
LDR R0, =EFC_BASE
LDR R1, =EFC1_FMR_Val
STR R1, [R0, #EFC1_FMR]
ENDIF
; Setup WDT
IF WDT_SETUP != 0
LDR R0, =WDT_BASE
LDR R1, =WDT_MR_Val
STR R1, [R0, #WDT_MR]
ENDIF
; Setup PMC
IF PMC_SETUP != 0
LDR R0, =PMC_BASE
; Setup Main Oscillator
LDR R1, =PMC_MOR_Val
STR R1, [R0, #PMC_MOR]
; Wait until Main Oscillator is stablilized
IF (PMC_MOR_Val:AND:PMC_MOSCEN) != 0
MOSCS_Loop LDR R2, [R0, #PMC_SR]
ANDS R2, R2, #PMC_MOSCS
BEQ MOSCS_Loop
ENDIF
; Setup the PLL
IF (PMC_PLLR_Val:AND:PMC_MUL) != 0
LDR R1, =PMC_PLLR_Val
STR R1, [R0, #PMC_PLLR]
; Wait until PLL is stabilized
PLL_Loop LDR R2, [R0, #PMC_SR]
ANDS R2, R2, #PMC_LOCK
BEQ PLL_Loop
ENDIF
; Select Clock
IF (PMC_MCKR_Val:AND:PMC_CSS) == 1 ; Main Clock Selected
LDR R1, =PMC_MCKR_Val
AND R1, #PMC_CSS
STR R1, [R0, #PMC_MCKR]
WAIT_Rdy1 LDR R2, [R0, #PMC_SR]
ANDS R2, R2, #PMC_MCKRDY
BEQ WAIT_Rdy1
LDR R1, =PMC_MCKR_Val
STR R1, [R0, #PMC_MCKR]
WAIT_Rdy2 LDR R2, [R0, #PMC_SR]
ANDS R2, R2, #PMC_MCKRDY
BEQ WAIT_Rdy2
ELIF (PMC_MCKR_Val:AND:PMC_CSS) == 3 ; PLL Clock Selected
LDR R1, =PMC_MCKR_Val
AND R1, #PMC_PRES
STR R1, [R0, #PMC_MCKR]
WAIT_Rdy1 LDR R2, [R0, #PMC_SR]
ANDS R2, R2, #PMC_MCKRDY
BEQ WAIT_Rdy1
LDR R1, =PMC_MCKR_Val
STR R1, [R0, #PMC_MCKR]
WAIT_Rdy2 LDR R2, [R0, #PMC_SR]
ANDS R2, R2, #PMC_MCKRDY
BEQ WAIT_Rdy2
ENDIF ; Select Clock
ENDIF ; PMC_SETUP
; Copy Exception Vectors to Internal RAM
IF :DEF:RAM_INTVEC
ADR R8, Vectors ; Source
LDR R9, =RAM_BASE ; Destination
LDMIA R8!, {R0-R7} ; Load Vectors
STMIA R9!, {R0-R7} ; Store Vectors
LDMIA R8!, {R0-R7} ; Load Handler Addresses
STMIA R9!, {R0-R7} ; Store Handler Addresses
ENDIF
; Remap on-chip RAM to address 0
MC_BASE EQU 0xFFFFFF00 ; MC Base Address
MC_RCR EQU 0x00 ; MC_RCR Offset
IF :DEF:REMAP
LDR R0, =MC_BASE
MOV R1, #1
STR R1, [R0, #MC_RCR] ; Remap
ENDIF
; Setup Stack for each mode
LDR R0, =Stack_Top
; Enter Undefined Instruction Mode and set its Stack Pointer
MSR CPSR_c, #Mode_UND:OR:I_Bit:OR:F_Bit
MOV SP, R0
SUB R0, R0, #UND_Stack_Size
; Enter Abort Mode and set its Stack Pointer
MSR CPSR_c, #Mode_ABT:OR:I_Bit:OR:F_Bit
MOV SP, R0
SUB R0, R0, #ABT_Stack_Size
; Enter FIQ Mode and set its Stack Pointer
MSR CPSR_c, #Mode_FIQ:OR:I_Bit:OR:F_Bit
MOV SP, R0
SUB R0, R0, #FIQ_Stack_Size
; Enter IRQ Mode and set its Stack Pointer
MSR CPSR_c, #Mode_IRQ:OR:I_Bit:OR:F_Bit
MOV SP, R0
SUB R0, R0, #IRQ_Stack_Size
; Enter Supervisor Mode and set its Stack Pointer
MSR CPSR_c, #Mode_SVC:OR:I_Bit:OR:F_Bit
MOV SP, R0
SUB R0, R0, #SVC_Stack_Size
; Enter User Mode and set its Stack Pointer
MSR CPSR_c, #Mode_USR
IF :DEF:__MICROLIB
EXPORT __initial_sp
ELSE
MOV SP, R0
SUB SL, SP, #USR_Stack_Size
ENDIF
; Enter the C code
IMPORT __main
LDR R0, =__main
BX R0
IF :DEF:__MICROLIB
EXPORT __heap_base
EXPORT __heap_limit
ELSE
; User Initial Stack & Heap
AREA |.text|, CODE, READONLY
IMPORT __use_two_region_memory
EXPORT __user_initial_stackheap
__user_initial_stackheap
LDR R0, = Heap_Mem
LDR R1, =(Stack_Mem + USR_Stack_Size)
LDR R2, = (Heap_Mem + Heap_Size)
LDR R3, = Stack_Mem
BX LR
ENDIF
END
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