本帖最后由 狂的风雨 于 2012-12-18 23:21 编辑
本人最近接触LPC1114单片机，发现多个GPIO口同时做输出，且us级波形时一直出现异常，波形如下：
源码主要是：
1）void SystemInit ()是system_LPC11xx.c中自带的，外边晶振为12MHz。
2）GPIO口的初始化主要是如下
LPC_SYSCON->SYSAHBCLKCTRL |= (1 << 6); /* 初始化GPIO AHB时钟 */
/*PD0-PD2,PCLR引脚*/
LPC_IOCON->JTAG_TDO_PIO1_1 &= ~0x07; /* 将P1.1初始化为GPIO功能 */
LPC_IOCON->JTAG_TDO_PIO1_1 |= 0x01;
LPC_IOCON->JTAG_TMS_PIO1_0 &= ~0x07; /* 将P1.0初始化为GPIO功能 */
LPC_IOCON->JTAG_TMS_PIO1_0 |= 0x01;
LPC_IOCON->JTAG_TDI_PIO0_11 &= ~0x07; /* 将P0.11初始化为GPIO功能 */
LPC_IOCON->JTAG_TDI_PIO0_11 |= 0x01;
/*设置PD0-PD2,PCLR（DD）如图为输出口*/
GPIOSetDir(1,1,1); /* 将P1.1设置为输出口 PD0 */
GPIOSetDir(1,0,1); /* 将P1.0设置为输出口 PD1 */
GPIOSetDir(0,11,1); /* 将P0.11设置为输出口 PD2 */
GPIOSetDir(2,11,1); /* 将P2.11设置为输出口 DD */
3）GPIOSetValue函数如下：
void GPIOSetValue( uint8_t portNum, uint8_t bitPosi, uint8_t bitVal )
{
/* if bitVal is 1, the bitPosi bit is set in the GPIOShadowPortx. Then
* GPIOShadowPortx is written to the I/O port register. */
LPC_GPIO[portNum]->MASKED_ACCESS[(1<<bitPosi)] = (bitVal<<bitPosi);
return;
}
4）main函数如下：
int main (void)
{
/*系统初始化*/
SystemInit();
/*通道板初始化*/
GPIOInit();
while(1)
{
/*PD0-PD2,PCLR输出值*/
GPIOSetValue(1,1,1);
GPIOSetValue(1,0,1);
GPIOSetValue(0,11,1);
GPIOSetValue(2,11,0);
delay_us(500);
GPIOSetValue(1,1,0);
GPIOSetValue(1,0,0);
GPIOSetValue(0,11,0);
GPIOSetValue(2,11,1);
delay_us(500);
};
}
注：该工程仅完成如上4个IO口的输出，且没有使用IO中断。
如上图所示，当延时时间越长输出的波形看不出来异常，但当延时时间为20us-10us 甚至更小时就会出现混乱。
分析代码没发现逻辑问题，就是一直找不到原因。请问各路大侠们有没遇到，怎么解决的，谢谢回复！
以下是我用的system_LPC11xx.c
#include <stdint.h>
#include "LPC11xx.h"
#define CLOCK_SETUP 1
#define MAIN_PLL_SETUP 1
#define MAIN_CLKSRCSEL_Val 0x00000001
#define MAIN_PLL_M_Val 0x00000003
#define MAIN_PLL_P_Val 0x00000001
#define SYS_AHB_DIV_Val 1 /* 1 through 255, typical is 1 or 2 or 4 */
/*
//-------- <<< end of configuration section >>> ------------------------------
*/
/*----------------------------------------------------------------------------
DEFINES
*----------------------------------------------------------------------------*/
/*----------------------------------------------------------------------------
Define clocks
*----------------------------------------------------------------------------*/
#define XTAL (12000000UL) /* Oscillator frequency */
#define OSC_CLK ( XTAL) /* Main oscillator frequency */
#define IRC_OSC ( 4000000UL) /* Internal RC oscillator frequency */
#define WDT_OSC ( 250000UL) /* WDT oscillator frequency */
/*----------------------------------------------------------------------------
Clock Variable definitions
*----------------------------------------------------------------------------*/
uint32_t ClockSource = IRC_OSC;
uint32_t SystemFrequency = IRC_OSC; /*!< System Clock Frequency (Core Clock) */
uint32_t SystemAHBFrequency = IRC_OSC;
/**
* Misc. clock generation modules
*
* @param none
* @return none
*
* @brief Setup the microcontroller system.
* Initialize the System and update the SystemFrequency variable.
*/
void Main_PLL_Setup ( void )
{
uint32_t regVal;
ClockSource = OSC_CLK;
LPC_SYSCON->SYSPLLCLKSEL = MAIN_CLKSRCSEL_Val; /* Select system OSC */
LPC_SYSCON->SYSPLLCLKUEN = 0x01; /* Update clock source */
LPC_SYSCON->SYSPLLCLKUEN = 0x00; /* toggle Update register once */
LPC_SYSCON->SYSPLLCLKUEN = 0x01;
while ( !(LPC_SYSCON->SYSPLLCLKUEN & 0x01) ); /* Wait until updated */
regVal = LPC_SYSCON->SYSPLLCTRL;
regVal &= ~0x1FF;
LPC_SYSCON->SYSPLLCTRL = (regVal | (MAIN_PLL_P_Val<<5) | MAIN_PLL_M_Val);
/* Enable main system PLL, main system PLL bit 7 in PDRUNCFG. */
LPC_SYSCON->;PDRUNCFG &= ~(0x1<<7);
while ( !(LPC_SYSCON->SYSPLLSTAT & 0x01) ); /* Wait until it's locked */
LPC_SYSCON->MAINCLKSEL = 0x03; /* Select PLL clock output */
LPC_SYSCON->MAINCLKUEN = 0x01; /* Update MCLK clock source */
LPC_SYSCON->MAINCLKUEN = 0x00; /* Toggle update register once */
LPC_SYSCON->MAINCLKUEN = 0x01;
while ( !(LPC_SYSCON->MAINCLKUEN & 0x01) ); /* Wait until updated */
LPC_SYSCON->SYSAHBCLKDIV = SYS_AHB_DIV_Val; /* SYS AHB clock, typical is 1 or 2 or 4 */
#if MAIN_PLL_SETUP
SystemFrequency = ClockSource * (MAIN_PLL_M_Val+1);
#else
SystemFrequency = ClockSource;
#endif
SystemAHBFrequency = (uint32_t)(SystemFrequency/SYS_AHB_DIV_Val);
return;
}
/**
* Initialize the system
*
* @param none
* @return none
*
* @brief Setup the microcontroller system.
* Initialize the System and update the SystemFrequency variable.
*/
void SystemInit (void)
{
uint32_t i;
#ifdef __DEBUG_RAM
LPC_SYSCON->SYSMEMREMAP = 0x1; /* remap to internal RAM */
#else
#ifdef __DEBUG_FLASH
LPC_SYSCON->SYSMEMREMAP = 0x2; /* remap to internal flash */
#endif
#endif
#if (CLOCK_SETUP) /* Clock Setup */
/* bit 0 default is crystal bypass,
bit1 0=0~20Mhz crystal input, 1=15~50Mhz crystal input. */
LPC_SYSCON->SYSOSCCTRL = 0x00;
/* main system OSC run is cleared, bit 5 in PDRUNCFG register */
LPC_SYSCON->;PDRUNCFG &= ~(0x1<<5);
/* Wait 200us for OSC to be stablized, no status
indication, dummy wait. */
for ( i = 0; i < 0x100; i++ );
#if (MAIN_PLL_SETUP)
Main_PLL_Setup();
#endif
#endif /* endif CLOCK_SETUP */
/* System clock to the IOCON needs to be enabled or
most of the I/O related peripherals won't work. */
LPC_SYSCON->SYSAHBCLKCTRL |= (1<<16);
return;
}
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