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可以$ Q+ v' I7 \+ f3 U
不过这个通常是需要看MCU的手册的，按照MCU手册上面的关于MEM CLOCK这部分% m7 v" [* Q+ T6 r
9 S- b! ]* U" f# u- @& w通常在系统启动的时候进行寄存器部分的设置拿三星的2410来说
5 ^: t4 ?9 t( p0 d! z4 R AREA Init,CODE,READONLY' F0 [5 j( A9 ^* I
ENTRY
+ U3 H' A4 h, ^) D b HandlerUndef ;handler for Undefined mode% J( K5 M8 p- w0 |
b HandlerSWI ;handler for SWI interrupt5 C" [. V9 E2 a. q+ ?
b HandlerPabort ;handler for PAbort
3 L* t. @' Y' }7 Q3 U; ?# \; v' P6 u b HandlerDabort ;handler for DAbort* i+ ~ ~. ^9 k& c
b . ;reserved/ _/ L- Z9 n# {! o
b HandlerIRQ ;handler for IRQ interrupt
2 ~9 |! \) C, g* i b HandlerFIQ ;handler for FIQ interrupt
; k" k- \$ _2 j) }+ J5 F初始化中断向量表。。。。
( a8 R2 x: ?: L6 y" ]8 e在初始化堆栈前必须做外部SDRAM内存的硬件初始化，这个时候就会根据硬件手册设置好相应的" ~/ ]- H& J/ u- T9 ?3 U! H( J
....................6 [+ E4 O. T, F. I0 \" i$ _
;Set memory control registers
+ _9 f/ G/ i; |# O( e, ^4 } ldr r0,=SMRDATA6 b9 N% r7 |/ P" i: ^( s+ ]
ldr r1,=BWSCON ;BWSCON Address
P* e5 K: Q3 | add r2, r0, #52 ;End address of SMRDATA
) q j: E' _4 z0 X" u# h7 V.................
; D. D& Y. Y s; ?;@0x207 A) L( ?0 V, \7 m
b EnterPWDN7 |, M. V$ |8 F9 d6 Z' V0 I! I0 J
SMRDATA DATA: z2 A6 s4 S& g, O0 t5 g
; Memory configuration should be optimized for best performance
- \0 S4 c0 B8 b" p' D( @# l6 ?: \# ~; The following parameter is not optimized.
' M4 i4 t- F- e; Memory access cycle parameter strategy
; \* k% A( q" u6 p; d5 U, `; 1) The memory settings is safe parameters even at HCLK=75Mhz.( ?) U1 v2 y# k+ r
; 2) SDRAM refresh period is for HCLK=75Mhz. z, @/ ?! O/ o' G
! V( l3 a- g8 _
DCD (0+(B1_BWSCON<<4)+(B2_BWSCON<<8)+(B3_BWSCON<<12)+(B4_BWSCON<<16)+(B5_BWSCON<<20)+(B6_BWSCON<<24)+(B7_BWSCON<<28))
2 p* b- [5 c$ X, K DCD ((B0_Tacs<<13)+(B0_Tcos<<11)+(B0_Tacc<<8)+(B0_Tcoh<<6)+(B0_Tah<<4)+(B0_Tacp<<2)+(B0_PMC)) ;GCS07 y. i0 u F% [4 b: X
DCD ((B1_Tacs<<13)+(B1_Tcos<<11)+(B1_Tacc<<8)+(B1_Tcoh<<6)+(B1_Tah<<4)+(B1_Tacp<<2)+(B1_PMC)) ;GCS1
" S0 Z! P' k/ x/ ~5 h9 C DCD ((B2_Tacs<<13)+(B2_Tcos<<11)+(B2_Tacc<<8)+(B2_Tcoh<<6)+(B2_Tah<<4)+(B2_Tacp<<2)+(B2_PMC)) ;GCS2
8 a8 S5 y6 f3 F# c DCD ((B3_Tacs<<13)+(B3_Tcos<<11)+(B3_Tacc<<8)+(B3_Tcoh<<6)+(B3_Tah<<4)+(B3_Tacp<<2)+(B3_PMC)) ;GCS30 R8 V+ p _* ?8 v
DCD ((B4_Tacs<<13)+(B4_Tcos<<11)+(B4_Tacc<<8)+(B4_Tcoh<<6)+(B4_Tah<<4)+(B4_Tacp<<2)+(B4_PMC)) ;GCS4
4 z: V* C- O/ i( E- k DCD ((B5_Tacs<<13)+(B5_Tcos<<11)+(B5_Tacc<<8)+(B5_Tcoh<<6)+(B5_Tah<<4)+(B5_Tacp<<2)+(B5_PMC)) ;GCS5) c/ h1 g5 s! R+ _% G
DCD ((B6_MT<<15)+(B6_Trcd<<2)+(B6_SCAN)) ;GCS6
5 x# M o# V9 z( h7 f1 E) p) v0 M DCD ((B7_MT<<15)+(B7_Trcd<<2)+(B7_SCAN)) ;GCS7
4 N0 f5 x4 N; j2 S' r+ o; k# [; DCD ((REFEN<<23)+(TREFMD<<22)+(Trp<<20)+(Trc<<18)+(Tchr<<16)+REFCNT) ;Tchr not used bit! ^5 T' }% R0 H* m% `; d6 e
DCD ((REFEN<<23)+(TREFMD<<22)+(Trp<<20)+(Trc<<18)+REFCNT)
% R9 `0 V. L2 \/ w
3 Z- C- b" V4 ~. A w9 d5 z6 {
- H# s( ~; K3 d& Q; DCD 0x32 ;SCLK power saving mode, ARM core burst disable, BANKSIZE 128M/128M
% L' n- @( s+ t) Y8 @ ]' l) v DCD 0xb2 ;SCLK power saving mode, ARM core burst enable , BANKSIZE 128M/128M - 11/29/20027 T) ]% v* f/ y j$ H7 a* h
d5 A' Q- o! \2 t- v
DCD 0x30 ;MRSR6 CL=3clk
$ D# C7 p4 O7 }# \4 M& Z DCD 0x30 ;MRSR7
0 S6 F( [. R" ~$ @! p- F- w4 q; DCD 0x20 ;MRSR6 CL=2clk
; ]5 o( K5 b& ?9 s; DCD 0x20 ;MRSR7 |
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发表于 2009-7-6 10:21
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