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可以 h- ~# v1 t ~2 R, l
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
% g4 Y# ^9 Q1 i! x5 ~; K' Q( N
I, I* [& Y8 e4 Q$ G, l5 g& l9 v3 T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
- }+ z5 y1 F x3 w% H AREA Init,CODE,READONLY: q4 d1 B) T Y8 m( K; `
ENTRY
' v5 a1 H: X# d! ^ b HandlerUndef ;handler for Undefined mode! R8 f0 U( Z) N! S _
b HandlerSWI ;handler for SWI interrupt8 f. t1 }. H: H5 R+ @" `
b HandlerPabort ;handler for PAbort
' ?- Q$ m4 L2 ?$ j# a W/ w b HandlerDabort ;handler for DAbort% U3 Y7 Q7 _( G6 t U
b . ;reserved' `6 [% H# N" o# @9 W
b HandlerIRQ ;handler for IRQ interrupt _$ K7 C V' ?( }/ |. q
b HandlerFIQ ;handler for FIQ interrupt. N, \: P# I/ W7 w
初始化中断向量表。。。。
# ]2 ?+ c; T9 C* p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
6 v5 S) u3 [; }1 j....................
, p5 D! i- g1 m1 @# {0 E- B ;Set memory control registers4 }7 z: e. H5 @9 V) l7 V
ldr r0,=SMRDATA
8 I5 i! @$ h \; O5 s0 D) A0 L" F ldr r1,=BWSCON ;BWSCON Address$ V" l, }7 @: L$ J2 @
add r2, r0, #52 ;End address of SMRDATA
$ \8 v4 t2 [% m+ n.................1 w3 {+ ]. C; j+ O2 b4 S/ q
;@0x20 e" l8 i, x/ p9 I# I( x( M4 F
b EnterPWDN. {) v9 [4 B' z% k' J
SMRDATA DATA9 d' v( D9 D5 I, X1 ?
; Memory configuration should be optimized for best performance + |7 G/ r6 V2 u0 O% J% ]9 t* p
; The following parameter is not optimized.
- Y& X, W" u" a; Memory access cycle parameter strategy
" p; B4 x# V5 `4 G; ^; 1) The memory settings is safe parameters even at HCLK=75Mhz.
! W" t; F$ {6 C& B6 K$ h; 2) SDRAM refresh period is for HCLK=75Mhz. # V' f M1 S" {" K8 n* m, J. `
. F/ l! x4 G: R- D; J0 n DCD (0+(B1_BWSCON<<4)+(B2_BWSCON<<8)+(B3_BWSCON<<12)+(B4_BWSCON<<16)+(B5_BWSCON<<20)+(B6_BWSCON<<24)+(B7_BWSCON<<28)); C- ~, k) ?$ U& E
DCD ((B0_Tacs<<13)+(B0_Tcos<<11)+(B0_Tacc<<8)+(B0_Tcoh<<6)+(B0_Tah<<4)+(B0_Tacp<<2)+(B0_PMC)) ;GCS0
% d$ ~7 ]: {) n) s DCD ((B1_Tacs<<13)+(B1_Tcos<<11)+(B1_Tacc<<8)+(B1_Tcoh<<6)+(B1_Tah<<4)+(B1_Tacp<<2)+(B1_PMC)) ;GCS1 7 [1 ]3 a% p4 M( i% ~
DCD ((B2_Tacs<<13)+(B2_Tcos<<11)+(B2_Tacc<<8)+(B2_Tcoh<<6)+(B2_Tah<<4)+(B2_Tacp<<2)+(B2_PMC)) ;GCS2- d6 M& A1 H$ [ R
DCD ((B3_Tacs<<13)+(B3_Tcos<<11)+(B3_Tacc<<8)+(B3_Tcoh<<6)+(B3_Tah<<4)+(B3_Tacp<<2)+(B3_PMC)) ;GCS3
8 z, u1 k1 P+ o# w$ o DCD ((B4_Tacs<<13)+(B4_Tcos<<11)+(B4_Tacc<<8)+(B4_Tcoh<<6)+(B4_Tah<<4)+(B4_Tacp<<2)+(B4_PMC)) ;GCS4
1 s* R9 [( Z9 E7 o" h DCD ((B5_Tacs<<13)+(B5_Tcos<<11)+(B5_Tacc<<8)+(B5_Tcoh<<6)+(B5_Tah<<4)+(B5_Tacp<<2)+(B5_PMC)) ;GCS5: t) {) {+ y( @' G
DCD ((B6_MT<<15)+(B6_Trcd<<2)+(B6_SCAN)) ;GCS6
/ k6 l) }& [" k' e/ z: A' b! ^ DCD ((B7_MT<<15)+(B7_Trcd<<2)+(B7_SCAN)) ;GCS77 \% m$ c, K. A9 @9 A
; DCD ((REFEN<<23)+(TREFMD<<22)+(Trp<<20)+(Trc<<18)+(Tchr<<16)+REFCNT) ;Tchr not used bit' n7 f6 s$ P2 ^" _
DCD ((REFEN<<23)+(TREFMD<<22)+(Trp<<20)+(Trc<<18)+REFCNT) / C2 `) C% {$ ?' |+ Z
8 k: W; t' S* P9 F& Y
; v' H3 H- y! a/ ~# ~0 e: k0 C
' `2 e3 u8 t8 Y
; DCD 0x32 ;SCLK power saving mode, ARM core burst disable, BANKSIZE 128M/128M
4 z- D+ \- t) G& u DCD 0xb2 ;SCLK power saving mode, ARM core burst enable , BANKSIZE 128M/128M - 11/29/2002
) ?4 H& i; Y: W" q3 R8 S
' f- c4 ^% k2 a- P2 J$ v8 L) i9 l DCD 0x30 ;MRSR6 CL=3clk
; Q1 K+ r+ U- A. P- X2 Q- m' g DCD 0x30 ;MRSR7
5 ?: \( `1 o1 |9 E5 k* u H3 F! y; DCD 0x20 ;MRSR6 CL=2clk% q5 E4 w6 e2 S: {
; DCD 0x20 ;MRSR7 |
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发表于 2009-7-6 10:21
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