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可以8 I5 i2 ~6 @# _
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
5 }% m3 l& j% J% y& K5 F9 L: t* {- V0 d
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
9 n4 c- Q1 i( w AREA Init,CODE,READONLY
4 ]: o$ [. _* h: g# C- J/ o ENTRY |; d5 f# D7 W
b HandlerUndef ;handler for Undefined mode2 m9 V+ z6 N- ]
b HandlerSWI ;handler for SWI interrupt
. C0 z1 j" ]+ @ f b HandlerPabort ;handler for PAbort
) b( C' [" T6 l8 g: q7 ?2 G% o b HandlerDabort ;handler for DAbort; y( D7 o A- d" v& d% ?0 ]$ ^
b . ;reserved
& X3 `- |. M. h, u+ K b HandlerIRQ ;handler for IRQ interrupt 9 c" b- s9 R( w' v F, U' u% [
b HandlerFIQ ;handler for FIQ interrupt
6 |' G8 f4 q; R/ [; w z& R初始化中断向量表。。。。
" }1 D/ T, m* o8 V& f/ A: I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
, D, e" V( B4 y3 D* V, ?/ E...................." l0 I% w2 E7 I& X
;Set memory control registers; b" B& _$ S; E# h$ I2 `
ldr r0,=SMRDATA
/ l. c5 X) A8 w9 ^- V ldr r1,=BWSCON ;BWSCON Address
. h- j# P' g& k' p add r2, r0, #52 ;End address of SMRDATA* K' ?+ w5 l# B
.................
/ f4 j2 G8 M! T: B i1 B;@0x20
( s0 `6 H2 J2 | C b EnterPWDN
+ Z# y! F- t$ [6 W# qSMRDATA DATA- j5 o1 N% i6 z; h
; Memory configuration should be optimized for best performance
3 U3 @! `" q* y( ?+ x w' c; The following parameter is not optimized.
2 z" a+ B' l% E: v# o2 i; Memory access cycle parameter strategy
& L. C4 x: o) Z% `; ~: p1 h; k; 1) The memory settings is safe parameters even at HCLK=75Mhz.
9 M' [/ ^4 R. F. s; 2) SDRAM refresh period is for HCLK=75Mhz.
3 c& ]: R" c4 j; Q
; a7 O2 f$ U0 s" V* R3 w% E( E DCD (0+(B1_BWSCON<<4)+(B2_BWSCON<<8)+(B3_BWSCON<<12)+(B4_BWSCON<<16)+(B5_BWSCON<<20)+(B6_BWSCON<<24)+(B7_BWSCON<<28))" c* D* r- }: q7 o1 _! u, } J0 o
DCD ((B0_Tacs<<13)+(B0_Tcos<<11)+(B0_Tacc<<8)+(B0_Tcoh<<6)+(B0_Tah<<4)+(B0_Tacp<<2)+(B0_PMC)) ;GCS0
9 ]# M) w0 ]' W DCD ((B1_Tacs<<13)+(B1_Tcos<<11)+(B1_Tacc<<8)+(B1_Tcoh<<6)+(B1_Tah<<4)+(B1_Tacp<<2)+(B1_PMC)) ;GCS1 # a' R# z" _2 I6 J
DCD ((B2_Tacs<<13)+(B2_Tcos<<11)+(B2_Tacc<<8)+(B2_Tcoh<<6)+(B2_Tah<<4)+(B2_Tacp<<2)+(B2_PMC)) ;GCS2
0 T; _# }8 u2 i DCD ((B3_Tacs<<13)+(B3_Tcos<<11)+(B3_Tacc<<8)+(B3_Tcoh<<6)+(B3_Tah<<4)+(B3_Tacp<<2)+(B3_PMC)) ;GCS3
) u! y; w* o9 b* l DCD ((B4_Tacs<<13)+(B4_Tcos<<11)+(B4_Tacc<<8)+(B4_Tcoh<<6)+(B4_Tah<<4)+(B4_Tacp<<2)+(B4_PMC)) ;GCS4
9 v F0 e) I) c/ G" U7 P DCD ((B5_Tacs<<13)+(B5_Tcos<<11)+(B5_Tacc<<8)+(B5_Tcoh<<6)+(B5_Tah<<4)+(B5_Tacp<<2)+(B5_PMC)) ;GCS54 z5 f% `( n. q- F
DCD ((B6_MT<<15)+(B6_Trcd<<2)+(B6_SCAN)) ;GCS6
; o- Y5 l7 E) ~ DCD ((B7_MT<<15)+(B7_Trcd<<2)+(B7_SCAN)) ;GCS7
( s. x K" e8 R# K6 V4 ~5 m% q; DCD ((REFEN<<23)+(TREFMD<<22)+(Trp<<20)+(Trc<<18)+(Tchr<<16)+REFCNT) ;Tchr not used bit: s1 L! j1 c' W
DCD ((REFEN<<23)+(TREFMD<<22)+(Trp<<20)+(Trc<<18)+REFCNT) 0 p4 l" j7 y H: F
& V1 U1 L I w; E! I9 j, q2 M5 N8 D5 h7 ?5 x. ?* I7 \
9 k9 x m' E* V$ M/ D6 u
; DCD 0x32 ;SCLK power saving mode, ARM core burst disable, BANKSIZE 128M/128M
# N; g3 b2 U% j" B P3 b DCD 0xb2 ;SCLK power saving mode, ARM core burst enable , BANKSIZE 128M/128M - 11/29/2002
% c2 K* z9 E$ h! `0 F) n( _. C- p
2 o* |3 R) T6 o DCD 0x30 ;MRSR6 CL=3clk
7 l4 a5 ]) U6 \! B* O5 W: E DCD 0x30 ;MRSR7
1 T- J8 k$ h2 M0 C7 Q, y, e; DCD 0x20 ;MRSR6 CL=2clk
' j) a6 M6 I+ [2 u; DCD 0x20 ;MRSR7 |
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发表于 2009-7-6 10:21
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