尝试使用52832单片机的模拟I2C与BQ25713通信,结果发现MCU给BQ25713发出START和ADDRESS（D7）之后，无法接收到BQ25713回复的ACK。下图是START开始的波形：
上方波形图的黄色为SDA、蓝色为SCL，在52832发送START及0xD7之后，SDA线无法收到BQ25713的ACK低电平。
采用单节电池设计，未配置情况下，VSYS电压为2.85V；
原理图如下：
请帮分析原因，谢谢。
代码如下：
#define Dev_Addr 0xD4
#define DevID_Addr 0X2F
#define PIN_IIC_SDA 34
#define PIN_IIC_SCL 32
#define SDA_H nrf_gpio_pin_write(PIN_IIC_SDA,1)
#define SDA_L nrf_gpio_pin_write(PIN_IIC_SDA,0)
#define SCL_H nrf_gpio_pin_write(PIN_IIC_SCL,1)
#define SCL_L nrf_gpio_pin_write(PIN_IIC_SCL,0)
#define SDA_read nrf_gpio_pin_read(PIN_IIC_SDA)
#define IIC_DELAY 10
//初始IIC
void BQ_25713_IIC_Init(void)
{
nrf_gpio_cfg_output(PIN_IIC_SDA);
nrf_gpio_cfg_output(PIN_IIC_SCL);
SCL_H;
SDA_H;
nrf_delay_us(IIC_DELAY);
}
//产生启始信号
void BQ_25713_IIC_Start(void)
{
SDA_OUT_BQ(); //sdaÏßÊä³ö
SDA_H;
SCL_H;
nrf_delay_us(IIC_DELAY);
SDA_L;//START:when CLK is high,DATA change form high to low
nrf_delay_us(IIC_DELAY);
SCL_L ;//ǯסI2C×ÜÏߣ¬×¼±¸·¢ËÍ»ò½ÓÊÕÊý¾Ý
}
//产生停止信号
void BQ_25713_IIC_Stop(void)
{
SDA_OUT_BQ();//sdaÏßÊä³ö
SCL_L;
SDA_L;//STOP:when CLK is high DATA change form low to high
nrf_delay_us(IIC_DELAY);
SCL_H;
SDA_H; //·¢ËÍI2C×ÜÏß½áÊøÐźÅ
nrf_delay_us(IIC_DELAY);
nrf_delay_us(10);
}
//等待应答
//·µ»ØÖµ£º1£¬½ÓÊÕÓ¦´ðʧ°Ü
// 0£¬½ÓÊÕÓ¦´ð³É¹¦
uint8_t BQ_25713_IIC_Wait_Ack(void)
{
uint8_t ucErrTime=0;
SDA_IN_BQ(); //SDAÉèÖÃΪÊäÈë
SDA_H;
nrf_delay_us(1);
SCL_H;
nrf_delay_us(IIC_DELAY);
while(SDA_read)
{
ucErrTime++;
if(ucErrTime>250)
{
BQ_25713_IIC_Stop();
return 1;
}
}
SCL_L ;//ʱÖÓÊä³ö0
nrf_delay_us(IIC_DELAY);
return 0;
}
//²úÉúACKÓ¦´ð
void BQ_25713_IIC_Ack(void)
{
SCL_L ;
SDA_OUT_BQ();
SDA_L;
nrf_delay_us(IIC_DELAY);
SCL_H;
nrf_delay_us(IIC_DELAY);
SCL_L ;
}
//²»²úÉúACKÓ¦´ð
void BQ_25713_IIC_NAck(void)
{
SCL_L ;
SDA_OUT_BQ();
SDA_H;
nrf_delay_us(IIC_DELAY);
SCL_H;
nrf_delay_us(IIC_DELAY);
SCL_L ;
}
//IIC·¢ËÍÒ»¸ö×Ö½Ú
//·µ»Ø´Ó»úÓÐÎÞÓ¦´ð
//1£¬ÓÐÓ¦´ð
//0£¬ÎÞÓ¦´ð
void BQ_25713_IIC_Send_Byte(uint8_t txd)
{
int i;
SDA_OUT_BQ();
SCL_L;
nrf_delay_us(IIC_DELAY);
for(i=0;i<8;i++)
{
if(txd&0x80)
SDA_H;
else
SDA_L;
txd<<=1;
nrf_delay_us(IIC_DELAY/2);
SCL_H;
nrf_delay_us(IIC_DELAY);
SCL_L;
nrf_delay_us(IIC_DELAY/2);
}
}
//¶Á1¸ö×Ö½Ú£¬ack=1ʱ£¬·¢ËÍACK£¬ack=0£¬·¢ËÍnACK
uint8_t BQ_25713_IIC_Read_Byte(unsigned char ack)
{
unsigned char i,receive=0;
SDA_IN_BQ();//SDAÉèÖÃΪÊäÈë
nrf_delay_us(IIC_DELAY);
for(i=0;i<8;i++ )
{
SCL_L ;
nrf_delay_us(IIC_DELAY);
SCL_H;
receive<<=1;
if(SDA_read)receive++;
nrf_delay_us(IIC_DELAY);
}
if (ack==0)
BQ_25713_IIC_NAck();//·¢ËÍnACK
else
BQ_25713_IIC_Ack(); //·¢ËÍACK
return receive;
}
void SDA_OUT_BQ(void)
{
nrf_gpio_cfg_output(PIN_IIC_SDA);
}
void SDA_IN_BQ(void)
{
nrf_gpio_cfg_input(PIN_IIC_SDA,NRF_GPIO_PIN_NOPULL);
}
uint8_t BQ25713_ReadOneByte(uint16_t ReadAddr)
{
uint8_t temp=0;
BQ_25713_IIC_Start();
BQ_25713_IIC_Send_Byte(Dev_Addr); //·¢ËÍдÃüÁî
BQ_25713_IIC_Wait_Ack();
BQ_25713_IIC_Send_Byte(ReadAddr); //·¢Ë͵͵ØÖ·
BQ_25713_IIC_Wait_Ack();
BQ_25713_IIC_Start();
BQ_25713_IIC_Send_Byte(Dev_Addr+1); //½øÈë½ÓÊÕģʽ
BQ_25713_IIC_Wait_Ack();
temp=BQ_25713_IIC_Read_Byte(0);
BQ_25713_IIC_Stop();//²úÉúÒ»¸öÍ£Ö¹Ìõ¼þ
return temp;
}
uint8_t BQ25713_Init(void)
{
uint8_t whoami;
/*¶ÁÈ¡WHO_AM_IÅжÏLIS3DHÊÇ·ñ´æÔÚ */
whoami=BQ25713_ReadOneByte(DevID_Addr);
USER_RTT("WHOMI= 0x%02x\r\n",(uint8_t)whoami);
if(whoami != 0x88)
{
USER_RTT("BQ25713 is not found!\r\n");
}
else
{
USER_RTT("BQ25713 is init ok ...\r\n");
}
}
