📄 嵌入式---程序示例1.htm
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<P align=center><A href="http://drew.nease.net/mypage/VxWorks.htm"><FONT
lang=ZH-CN face=System>VxWorks</FONT></A></P></TD>
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color=#0000ff><BIG><BIG><BIG>程序示例</BIG></BIG></BIG></FONT></P>
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<P><BIG><STRONG>
这里是一些程序示例和源码解释.一些相关程序代码会陆续补上.相关问题可参见</STRONG></BIG><A
href="http://drew.nease.net/mypage/driver.htm" target=_blank><FONT lang=ZH-CN
face=System>硬件驱动</FONT></A></P>
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<TD width=254 height=33><B><A
href="http://drew.nease.net/mypage/sourcecode.htm#INIT">系统初始化(PowerPC汇编)</A>
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<TD width=263 height=33><A
href="http://drew.nease.net/mypage/example/config.htm"><B>VxWorks
BSP文件配置及生成下载</B></A><B> </B></TD></TR>
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href="http://drew.nease.net/mypage/sourcecode.htm#INT"><B>硬件中断</B></A></TD>
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href="http://drew.nease.net/mypage/sourcecode.htm#NIC"><B>VxWorks网络驱动</B></A></TD></TR>
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<TD width=254 height=33><A
href="http://drew.nease.net/mypage/example/flashrom.htm"><B>FlashROM驱动(ARM汇编)</B></A></TD>
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href="http://drew.nease.net/mypage/example/ARM_Boot.htm"><B>ARM Boot
Load程序(ARM汇编)</B></A></TD></TR>
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<TD width=254 height=34><A
href="http://drew.nease.net/mypage/example/UART.htm"><B>串口(UART)程序示例</B></A></TD>
<TD width=263 height=34><A
href="http://drew.nease.net/mypage/example/pci.htm"><U><B>PCI设备(网卡)初始化代码分析</B></U></A></TD></TR>
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<TD width=254 height=34><U><B>文件系统</B></U></TD>
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<TD width=254 height=34><A
href="http://drew.nease.net/mypage/sourcecode.htm#LCD"><B>LCD和触摸屏</B></A></TD>
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href="http://drew.nease.net/mypage/sourcecode.htm#MODEM"><B>MODEM
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<TD width=254 height=34><B><A
href="http://drew.nease.net/mypage/sourcecode.htm#RTC">实时时钟 RTC</A>
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<BLOCKQUOTE>
<P> </P></BLOCKQUOTE>
<P><A name=INIT></A><BIG><BIG><STRONG>系统初始化</STRONG></BIG></BIG></P>
<BLOCKQUOTE>
<P><STRONG>系统初始化对不同的CPU,基本步骤是类似的.</STRONG></P>
<P><STRONG>系统初始化的主要步骤如下</STRONG></P>
<BLOCKQUOTE>
<UL>
<LI><STRONG>启动</STRONG>
<LI><STRONG>关闭中断</STRONG>
<LI><STRONG>放boot type到堆栈</STRONG>
<LI><STRONG>清空缓存</STRONG> </LI></UL></BLOCKQUOTE>
<P><STRONG>VxWorks 系统的 PowerPC BSP,系统开机后执行的第一个函数
romInit(),在ROM的起点,这里是使用的PowerPC汇编语言</STRONG></P>
<BLOCKQUOTE>
<P>/* 定义内部函数 internals */<BR>.globl romInit /* start of system code
*/<BR>.globl _romInit /* start of system code */<BR><BR>/* 定义外部函数 externals
*/<BR>.extern romStart /* system initialization routine
*/<BR><BR>.text<BR>.align
2<BR><BR>/*******************************************************************************<BR>*
<BR>* romInit ( int startType /@ only used by 2nd entry point @/
)<BR>*/<BR><BR>romInit:<BR>_romInit:<BR>bl cold /* 冷启动
*/<BR>bl warm /* 热启动 */<BR><BR>cold:<BR>li p5,
BOOT_COLD<BR>bl start /* skip over next instruction */<BR><BR>warm:<BR>or
p5, p0, p0 /* startType to p5
*/<BR><BR>start: /*
<STRONG>此处是系统启动开始</STRONG> */</P>
<P>/* <STRONG>屏蔽MSR中CE,EE位,关闭所有的外部中断</STRONG><BR>/*<BR>* Disable external
interrupts <BR>*/<BR><BR>mfmsr p0 /* p0 = msr */<BR>INT_MASK (p0, p1) /*
mask EE and CE bit */<BR>ori p1,p1,_PPC_MSR_ME /* enable machine checks
*/<BR>mtmsr p1 /* msr = p1 */<BR>isync<BR><BR>/*
<STRONG>下面两步是按照硬件定义初始化一些SPR,DCR寄存器,置0或置1</STRONG></P>
<P><STRONG>/*
SPR是特殊功能寄存器,DCR为设备控制寄存器,还有MSR机器状态寄存器,这些是PowerPC内核中很重要的寄存器</STRONG></P>
<P>/* 初始化SPR,DCR寄存器置0<BR>* Initalize registers that need to be set to
zero.<BR>*/<BR><BR>addi r4,r0,0x0000<BR>mtspr SGR,r4 /* 解锁所有存储区域 SPR 中 SGR
位置0 */<BR>mtspr ESR, r4 /* SPR中的错误状态位 ESR 清0 */<BR>mtspr TCR, r4 /* 关闭所有的
timers */<BR>mtspr PIT, r4 /* 清0 PIT timer */<BR>mtdcr UICER, r4 /*
关闭中断控制器(UIC)中的所有中断 */<BR>mtspr XER, r4 /* 清0 integer exception 寄存器
*/<BR><BR>/* 初始化另一些SPR,DCR寄存器置1<BR>* Initalize registers that need to be
cleared with 0xFFFFFFFF.<BR>*/<BR><BR>addis r4,r0,0xffff<BR>ori
r4,r4,0xffff<BR>mtspr TSR, r4 /* timer */<BR>mtspr DBSR, r4 /* 调试状态位置1
*/<BR>mtdcr UICSR, r4 /* 清除中断控制器(UIC)中的所有 pending 中断 */<BR>mtdcr dmasr, r4
/* DMA状态寄存器置1 */<BR><BR>/*
<STRONG>PowerPC405用两个缓存,一个是16K指令缓存(ICU),一个是6K数据缓存(DCU),下面是清空着两个缓存,并根据硬件设置缓存</STRONG>
*/</P>
<P>/* 清空指令缓存 */<BR>/*BESR type regs ZZZZZZZZZZZZ <BR>* Invalidate the entire
instruction cache. This can be done<BR>* with a single iccci instruction in
the processor core.<BR>*/<BR><BR>iccci r0, r0<BR><BR>/*清空数据缓存<BR>*
Invalidate the entire data cache.<BR>* The 405 processor core in the 405GP
has 128 congruence classes.<BR>* Each cache line in the 405 processor is 32
bytes.<BR>*/<BR><BR>/*<BR>* Turn the instruction cache on for faster
boot-up.<BR>* Also, the icache is needed to help initialize Bank 0<BR>* of
the EBC to speed up accesses to flash.<BR>* address space
0x00000000-0x07ffffff is cached<BR>* address space 0xf8000000-0xffffffff is
cached<BR>*/<BR><BR>lis p0, HIADJ(_PPC403_ICCR_DEFAULT_VAL)<BR>addi p0, p0,
LO(_PPC403_ICCR_DEFAULT_VAL)<BR>mtspr _PPC403_ICCR,
p0<BR>isync<BR><BR>/*<STRONG>
初始化外部总线控制器(EBC)</STRONG>,<STRONG>跳转指令BL,执行extBusCntlrInit</STRONG><BR>*
/<BR><BR>bl extBusCntlrInit<BR><BR>/*<BR>* Now that the EBC Bank 0 has been
set up, turn the I-cache off if<BR>* i-cache was not specified in config.h.
It is also invalidated<BR>* again.<BR>*/<BR><BR>#ifndef
USER_I_CACHE_ENABLE<BR>li p0, 0 /* clear p0 */<BR>mtspr _PPC403_ICCR, p0 /*
turn off i-cache */<BR>isync<BR>iccci r0, r0 /* invalidate the I-cache again
*/<BR>#endif<BR><BR>/* 初始化和SDRAM相关的IIC(inter-integrated circut)寄存器IIC0,<BR>*
Initialize IIC0 for use in automatic SDRAM configuration<BR>*/<BR><BR>#ifdef
LOCAL_MEM_AUTOSIZE<BR>bl iic0Init<BR>#endif<BR><BR>/*
<STRONG>初始化SDRAM</STRONG>,<STRONG>BL跳转执行sdramInit</STRONG><BR>* Configure
the SDRAM controller only if this is a cold boot.<BR>* If the SDRAM
controller is reinitialized on a warm boot, the<BR>* boot line will get
wiped out because of the ECC SDRAM memory<BR>*
initialization.<BR>*/<BR><BR>li p0, BOOT_COLD<BR>and. p0, p0, p5 /* p5 is
saved at the entry of romInit */<BR>beq skip<BR><BR>bl
sdramInit<BR><BR>skip:<BR><BR>/*<BR>* Clear the CPU reservation
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