_word()用法

在所有的2410或者arm9 的开发板都会用到一个SDRAM.INI，并且里面都用到了__word( , )的这个指令。那这个指令是什么意思呢？今天我们就来解析一下。

__word( , )是keil软件中自带的一个指令，他的用法是，把某个地址处写如相应的值，相当于把某个地址的寄存器初始化。我们任举一例，_WDWORD(0x53000000, 0x00000000); 这个是从所有2410的工程中用到的sdram.ini中copy的一句话，我们查看2410的手册发现，0x53000000这个地址就是看门狗的控制寄存器，写入0x00000000就是关闭看门狗。想必现在大家都懂了吧。下面是sdram.ini这个文件的_word()指令简单注释。希望对大家有帮助。

/******************************************************************************/

/* */

SDRAM.INI: External RAM (SDRAM) Initialization File

/******************************************************************************/

// //

<<< 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. */

/******************************************************************************/

FUNC void Setup (void) {

_WDWORD(0x53000000, 0x00000000); //关闭看门狗

_WDWORD(0x4A000008, 0xFFFFFFFF); // 关闭相应中断

_WDWORD(0x4A00001C, 0x000007FF); // 关闭相应中断

_WDWORD(0x4C000014, 0x00000003);

_WDWORD(0x4C000004, 0x0005c042); // 时钟分频

_WDWORD(0x56000070, 0x00280000); //

_WDWORD(0x56000078, 0x00000000);

_WDWORD(0x48000000, 0x22111110); _WDWORD(0x48000004, 0x00000700);

_WDWORD(0x48000008, 0x00000700);

_WDWORD(0x4800000C, 0x00000700);

_WDWORD(0x48000010, 0x00000700);

_WDWORD(0x48000014, 0x00000700);

_WDWORD(0x48000018, 0x00000700);

_WDWORD(0x4800001c, 0x00018005);

_WDWORD(0x48000020, 0x00000700);

_WDWORD(0x48000024, 0x008e0459);

//SARAM 初始化

_WDWORD(0x48000028, 0x000000B2);

_WDWORD(0x4800002c, 0x00000030);

_WDWORD(0x48000030, 0x00000030);

_WDWORD(0x56000014, 0x00000001);

_WDWORD(0x56000020, 0xAAAA55AA); //lcd管脚初始化

_WDWORD(0x56000028, 0x0000FFFF);

_WDWORD(0x56000024, 0x00000000);

}

Setup(); // Setup for Init

LOAD SDRAM\\StepMotor_Test.axf INCREMENTAL // Download

PC = 0x30000000; // Program Entry Point

g, main // Run to main function