149 lines
3.2 KiB
C
149 lines
3.2 KiB
C
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#include "main.h"
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uint8_t BYTE_BUF[2];
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//I2C GPIO初始化
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void I2C_Init(void)
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{
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rcu_periph_clock_enable(RCU_GPIOB); //使能GPIOB时钟
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// PB6--SCL,PB7--SDA.(I2C0)
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gpio_mode_set(GPIOB, GPIO_MODE_OUTPUT, GPIO_PUPD_NONE, GPIO_PIN_6 | GPIO_PIN_7);
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gpio_output_options_set(GPIOB, GPIO_OTYPE_PP, GPIO_OSPEED_50MHZ, GPIO_PIN_6 | GPIO_PIN_7);
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gpio_bit_set(GPIOB, GPIO_PIN_6 | GPIO_PIN_7);
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}
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//产生IIC起始信号
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void IIC_Start(void)
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{
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//SDA_OUT(); //sda线输出
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IIC_SDA_SET;
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IIC_SCL_SET;
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delay_us(4);
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IIC_SDA_RET; //START:when CLK is high,DATA change form high to low
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delay_us(4);
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IIC_SCL_RET; //钳住I2C总线，准备发送或接收数据
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}
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//产生IIC停止信号
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void IIC_Stop(void)
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{
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//SDA_OUT(); //sda线输出
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IIC_SCL_RET;
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IIC_SDA_RET; //STOP:when CLK is high DATA change form low to high
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delay_us(4);
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IIC_SCL_SET;
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IIC_SDA_SET; //发送I2C总线结束信号
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delay_us(4);
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}
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//等待应答信号到来
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//返回值：1，接收应答失败
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// 0，接收应答成功
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uint8_t IIC_Wait_Ack(void)
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{
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uint8_t ucErrTime = 0;
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//SDA_IN(); //SDA设置为输入
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IIC_SDA_SET;
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delay_us(1);
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IIC_SCL_SET;
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delay_us(1);
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while (READ_SDA)
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{
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ucErrTime++;
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if (ucErrTime > 250)
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{
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IIC_Stop();
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return 1;
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}
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delay_us(1);
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}
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IIC_SCL_RET; //时钟输出0
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return 0;
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}
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//产生ACK应答
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void IIC_Ack(void)
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{
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IIC_SCL_RET;
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//SDA_OUT();
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IIC_SDA_RET;
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delay_us(2);
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IIC_SCL_SET;
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delay_us(2);
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IIC_SCL_RET;
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}
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//不产生ACK应答
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void IIC_NAck(void)
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{
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IIC_SCL_RET;
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//SDA_OUT();
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IIC_SDA_SET;
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delay_us(2);
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IIC_SCL_SET;
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delay_us(2);
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IIC_SCL_RET;
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}
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//IIC发送一个字节
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//返回从机有无应答
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//1，有应答
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//0，无应答
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void IIC_Send_Byte(uint8_t txd)
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{
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uint8_t t;
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//SDA_OUT();
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IIC_SCL_RET; //拉低时钟开始数据传输
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for (t = 0; t < 8; t++)
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{
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if ((txd & 0x80) >> 7)
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IIC_SDA_SET;
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else
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IIC_SDA_RET;
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txd <<= 1;
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delay_us(2); //对TEA5767这三个延时都是必须的
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IIC_SCL_SET;
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delay_us(2);
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IIC_SCL_RET;
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delay_us(2);
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}
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}
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//读1个字节，ack=1时，发送ACK，ack=0，发送nACK
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uint8_t IIC_Read_Byte(unsigned char ack)
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{
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unsigned char i, receive = 0;
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//SDA_IN(); //SDA设置为输入
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for (i = 0; i < 8; i++)
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{
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IIC_SCL_RET;
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delay_us(2);
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IIC_SCL_SET;
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receive <<= 1;
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if (READ_SDA)
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receive++;
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delay_us(1);
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}
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if (!ack)
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IIC_NAck(); //发送nACK
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else
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IIC_Ack(); //发送ACK
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return receive;
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}
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uint8_t LTC2451_NewConv(void)
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{
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IIC_Start();
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IIC_Send_Byte(LTC2451_ADDR_W);
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if (IIC_Wait_Ack() != 0)
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return 1;
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IIC_Stop();
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return 0;
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}
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uint8_t LTC2451_ReadAdc(uint16_t *adc_value)
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{
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uint8_t temp[2];
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IIC_Start();
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IIC_Send_Byte(LTC2451_ADDR_R);
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if (IIC_Wait_Ack() != 0)
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return 1;
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temp[0] = IIC_Read_Byte(1);
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temp[1] = IIC_Read_Byte(0);
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IIC_Stop(); //产生一个停止条件
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*adc_value = (temp[0] << 8) + temp[1];
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return 0;
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}
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