MCP4725 用IIC进行通讯,输出的电压值只有0.1V左右,而且VOUT一直不变,有人知道是什么问题吗?
MCP4725代码:
#include "./MCP/MCP4725.h"
#include "./delay/delay.h"
#include "./usart/bsp_usart.h"
#include "bsp_SysTick.h"
void MCP4725_Init(void)
{
IIC_Init();
//MCP4725_WriteData_Voltage(MCP4725_Init_Value);
}
void MCP4725_WriteData_Voltage(u16 Vout)
{
u8 temp;
u16 Dn;
if(Vout>=5000) Vout=4999;
Dn = ( 4096 * Vout) / VREF_5V;
temp = (0x0F00 & Dn) >> 8;
IIC_Start();
IIC_Send_Byte(0XC0);
IIC_Wait_Ack();
IIC_Send_Byte(temp);
IIC_Wait_Ack();
IIC_Send_Byte(Dn);
IIC_Wait_Ack();
IIC_Stop();
delay_ms(10);
}
void MCP4725_WriteData_Digital(u16 data)
{
u8 data_H=0,data_L=0;
data_H = ( 0x0F00 & data) >> 8;
data_L = 0X00FF & data ;
IIC_Start();
IIC_Send_Byte(0xC0);
IIC_Wait_Ack();
IIC_Send_Byte(data_H);
IIC_Wait_Ack();
IIC_Send_Byte(data_L);
IIC_Wait_Ack();
IIC_Stop();
delay_ms(10);
}
i2c代码:
#include "./i2c/bsp_i2c_ee.h"
#include "./delay/delay.h"
#include "Device/Include/stm32f10x.h" // Device header
#include "bsp_SysTick.h"
void IIC_Init(void)
{
GPIO_InitTypeDef GPIO_InitStructure;
RCC_APB2PeriphClockCmd( RCC_APB2Periph_GPIOB, ENABLE ); //ʹÄÜGPIOBʱÖÓ
GPIO_InitStructure.GPIO_Pin = GPIO_Pin_6|GPIO_Pin_7; //PB6 ->SCL; PB7->SDA
GPIO_InitStructure.GPIO_Mode = GPIO_Mode_Out_OD ; //¿ªÂ©Êä³ö
GPIO_InitStructure.GPIO_Speed = GPIO_Speed_50MHz;
GPIO_Init(GPIOB, &GPIO_InitStructure);
GPIO_SetBits(GPIOB,GPIO_Pin_6|GPIO_Pin_7);
}
void SDA_IN (void)
{
GPIO_InitTypeDef GPIO_InitStructure;
RCC_APB2PeriphClockCmd( RCC_APB2Periph_GPIOB, ENABLE );
GPIO_InitStructure.GPIO_Pin = GPIO_Pin_7;
GPIO_InitStructure.GPIO_Mode = GPIO_Mode_IN_FLOATING;
GPIO_Init(GPIOB, &GPIO_InitStructure);
}
void SDA_OUT(void)
{
GPIO_InitTypeDef GPIO_InitStructure;
RCC_APB2PeriphClockCmd( RCC_APB2Periph_GPIOB, ENABLE );
GPIO_InitStructure.GPIO_Pin = GPIO_Pin_7;
GPIO_InitStructure.GPIO_Mode = GPIO_Mode_Out_OD ;
GPIO_InitStructure.GPIO_Speed = GPIO_Speed_50MHz;
GPIO_Init(GPIOB, &GPIO_InitStructure);
}
void IIC_Start(void)
{
SDA_OUT();
IIC_SDA=1;
IIC_SCL=1;
delay_us(16);
IIC_SDA=0;
delay_us(16);
IIC_SCL=0;
}
void IIC_Stop(void)
{
SDA_OUT();
IIC_SCL=0;
IIC_SDA=0;//STOP:when CLK is high DATA change form low to high
delay_us(16);
IIC_SCL=1;
IIC_SDA=1;
delay_us(16);
}
u8 IIC_Wait_Ack(void)
{
u8 ucErrTime=0;
SDA_IN();
IIC_SDA=1;delay_us(4);
IIC_SCL=1;delay_us(4);
while(READ_SDA)
{
ucErrTime++;
if(ucErrTime>250)
{
IIC_Stop();
return 1;
}
}
IIC_SCL=0;
return 0;
}
void IIC_Ack(void)
{
IIC_SCL=0;
SDA_OUT();
IIC_SDA=0;
delay_us(8);
IIC_SCL=1;
delay_us(8);
IIC_SCL=0;
}
void IIC_NAck(void)
{
IIC_SCL=0;
SDA_OUT();
IIC_SDA=1;
delay_us(8);
IIC_SCL=1;
delay_us(8);
IIC_SCL=0;
}
void IIC_Send_Byte(u8 txd)
{
u8 t;
SDA_OUT();
IIC_SCL=0;
for(t=0;t<8;t++)
{
//IIC_SDA=(txd&0x80)>>7;
if((txd&0x80)>>7)
IIC_SDA=1;
else
IIC_SDA=0;
txd<<=1;
delay_us(8);
IIC_SCL=1;
delay_us(8);
IIC_SCL=0;
delay_us(8);
}
}
u8 IIC_Read_Byte(unsigned char ack)
{
unsigned char i,receive=0;
SDA_IN();
for(i=0;i<8;i++ )
{
IIC_SCL=0;
delay_us(8);
IIC_SCL=1;
receive<<=1;
if(READ_SDA)receive++;
delay_us(4);
}
if (!ack)
IIC_NAck();
else
IIC_Ack();
return receive;
}