请教原子哥，STM32的ACK这个信号我一直收不到是为什么呢，我是硬件IIC1，读PCF8563芯片，但是没有办法收到那个ACK信号
void I2C_Mode_config(void)
{

I2C_InitTypeDef I2C_InitStructure;//?¨??I2C?á????

//?ò??I2C1?±??
RCC_APB1PeriphClockCmd(RCC_APB1Periph_I2C1,ENABLE);


I2C_InitStructure.I2C_Mode = I2C_Mode_I2C;//????I2C??I2C????

I2C_InitStructure.I2C_DutyCycle = I2C_DutyCycle_2;//?????????ì???¤×÷?????????§

I2C_InitStructure.I2C_OwnAddress1 =0x0A;//???è???·

I2C_InitStructure.I2C_Ack = I2C_Ack_Enable ;//????????

I2C_InitStructure.I2C_AcknowledgedAddress = I2C_AcknowledgedAddress_7bit;//ATC24C02???·??7??

I2C_InitStructure.I2C_ClockSpeed = 400000;//×?????400KHz

I2C_Cmd(I2C1, ENABLE);//????I2C

I2C_Init(I2C1, &I2C_InitStructure);
}


unsigned char i2c_write_n_bytes(unsigned char SLA_W, unsigned int ADDR,unsigned int N, unsigned char *DAT)
{
unsigned int i;

I2C_GenerateSTART(I2C1, ENABLE);//?ú?ú??????
while(!I2C_CheckEvent(I2C1, I2C_EVENT_MASTER_MODE_SELECT)); //

I2C_Send7bitAddress(I2C1, SLA_W, I2C_Direction_Transmitter);//

I2C_EE_WaitEepromStandbyState();

while(!I2C_CheckEvent(I2C1,I2C_EVENT_MASTER_TRANSMITTER_MODE_SELECTED));

I2C_SendData(I2C1, (unsigned char)ADDR); //

while(! I2C_CheckEvent(I2C1, I2C_EVENT_MASTER_BYTE_TRANSMITTED));//
for(i=0;i<N;i++)
{

I2C_SendData(I2C1, *(DAT+i));

while(! I2C_CheckEvent(I2C1, I2C_EVENT_MASTER_BYTE_TRANSMITTED));//

}

I2C_GenerateSTOP(I2C1, ENABLE);//
return 1;
}