/****************************************************************************
*   Copyright: (C)2021 武汉凌云物网智科实验室 www.iot-yun.com
*      Author: GuoWenxue<guowenxue@gmail.com> QQ: 281143292
* Description: 凌云IoT Starter IoT Kits开发板 温度传感器DS18B20采样API函数。
*
*              SHT20温度传感器使用GPIO模拟I2C总线I2C0
*
*   ChangeLog:
*        版本号     日期       作者      说明
*        V1.0.0  2021.06.18  GuoWenxue   发布该版本
****************************************************************************/

#include <stdio.h>
#include "stm32f1xx_hal.h"
#include "tim.h"

#define W1DQ_Set_Input()	   	\
{	\
		GPIO_InitTypeDef GPIO_InitStruct = {0}; \
		GPIO_InitStruct.Pin = W1Dat_Pin; \
		GPIO_InitStruct.Mode = GPIO_MODE_INPUT; \
		GPIO_InitStruct.Pull = GPIO_PULLUP; \
		HAL_GPIO_Init(W1Dat_GPIO_Port, &GPIO_InitStruct); \
}

#define W1DQ_Set_Output()	   	\
{	\
		GPIO_InitTypeDef GPIO_InitStruct = {0}; \
		GPIO_InitStruct.Pin = W1Dat_Pin; \
		GPIO_InitStruct.Mode = GPIO_MODE_OUTPUT_PP; \
		GPIO_InitStruct.Speed = GPIO_SPEED_FREQ_HIGH; \
		GPIO_InitStruct.Pull = GPIO_PULLUP; \
		HAL_GPIO_Init(W1Dat_GPIO_Port, &GPIO_InitStruct); \
}

#define HIGH      1
#define LOW       0

#define W1DQ_WritePin(N)   HAL_GPIO_WritePin(W1Dat_GPIO_Port, W1Dat_Pin, N!=0?GPIO_PIN_SET:GPIO_PIN_RESET)
#define W1DQ_ReadPin()     HAL_GPIO_ReadPin(W1Dat_GPIO_Port,  W1Dat_Pin)

/*  Description: reset DS18B20 and wait for respond signal
 * Return Value: 0: OK   -1: No respond signal  -2: No reset end signal
 */
int ds18b20_init(void)
{
	  uint8_t            retry=0;
	  int                rv = 0;

	  /* 1-Wire Data Pin set as output mode */
	  W1DQ_Set_Output();

	  /* Master send a reset signal of 480~960 µs */
	  W1DQ_WritePin(LOW);
	  delay_us(750);
	  W1DQ_WritePin(HIGH);

	  /* When the DS18B20 detects this rising edge, it waits 15~60µs  */
	  delay_us(15);

	  /* Master then releases the bus and goes into receive mode. When the
	   * bus is released, the 5kΩ pullup resistor pulls the 1-Wire bus high. */
	  W1DQ_Set_Input();

	  /* Then DS18B20 will transmits a presence pulse by pulling the 1-Wire bus low for 60~240µs. */
	  while ( W1DQ_ReadPin() && retry<240 )
	  {
		  retry++;
		  delay_us(1);
	  }

	  if(retry>=240)
	  {
		  rv = -1;
		  goto OUT;
	  }

	  /* Then DS18B20 release bus and resistor will pull-up the bus high for 60~240µs. */
	  retry=0;
	  while ( !W1DQ_ReadPin() && retry<240 )
	  {
		  retry++;
		  delay_us(1);
	  }

	  if(retry>=240)
	  {
		  rv = -2;
		  goto OUT;
	  }

	OUT:
	  if( rv )
	  {
		  printf("ERROR: DS18B20 check respond signal failure, rv=%d\r\n", rv);
	  }
	  return rv;
}



/* Description: Write a byte data to DS18B20 */
void w1bus_write_byte(uint8_t byte)
 {
	uint8_t         i;
	uint8_t         testb;

	/* 1-Wire Data Pin set as output mode */
	W1DQ_Set_Output();

    for(i=1; i<=8; i++)
    {
      testb=byte&0x01; //取最低位
      byte=byte>>1;

      if (testb)
      {
    	  /* write bit 1:  */
    	  W1DQ_WritePin(LOW);
    	  delay_us(2);

    	  W1DQ_WritePin(HIGH);
    	  delay_us(60);
      }
      else
      {
    	  /* write bit 0 */
    	  W1DQ_WritePin(LOW);
    	  delay_us(60);

    	  W1DQ_WritePin(HIGH);
    	  delay_us(2);
      }
    }
}

/* Description: Read a bit from DS18B20 */
uint8_t w1bus_read_bit(void)
{
	uint8_t  bit;

	/* 1-Wire Data Pin set as output mode */
	W1DQ_Set_Output();

    /*Generate read time slot*/
    W1DQ_WritePin(LOW);
    delay_us(2);
    //W1DQ_WritePin(HIGH);

	/*Master must read data from slave in 15us*/
    W1DQ_Set_Input();
	delay_us(8);
	bit = W1DQ_ReadPin() ? 1 : 0;

	delay_us(50);

	return bit;
}

/* 从DS18B20读取一个字节 */
uint8_t w1bus_read_byte(void)
{
	uint8_t       i,j,byte;

    byte=0;
    for(i=1; i<=8; i++)
    {
      j=w1bus_read_bit();
      byte=(j<<7)|(byte>>1);
    }

    return byte;
}


int ds18b20_start_convert(void)
{
	int          rv = 0;

	if( 0 != (rv=ds18b20_init()) )
		return rv;

	w1bus_write_byte(0xCC);  // Master issues Skip ROM command.
	w1bus_write_byte(0x44);  // Master issues Convert T command.

	return 0;
}


int ds18b20_start_readreg(void)
{
	int          rv = 0;

	if( 0 != (rv=ds18b20_init()) )
		return rv;

	w1bus_write_byte(0xCC);  // Master issues Skip ROM command.
	w1bus_write_byte(0xBE);  // Master issues Read Scratchpad command.

	return 0;
}

int ds18b20_get_temperature(float *temperature)
{
	uint8_t       sign;
	uint8_t       TL,TH;
	uint16_t      tmp;
	int           rv;
	float         temp;


	if( 0 != (rv=ds18b20_start_convert()) )
		return rv;

	if( 0 != (rv=ds18b20_start_readreg()) )
		return rv;

    TL=w1bus_read_byte(); // LSB
    TH=w1bus_read_byte(); // MSB

    printf("DS18B20 Read TH[0x%02x] TH[0x%02x]\r\n", TH, TL);

    if(TH>7) /* 高5位为1，说明温度为负 */
    {
      tmp = ~(TH<<8|TL) + 1;  //补码
      sign=0;//温度为负
    }
    else
    {
      sign=1;//温度为正
      tmp = TH<<8 | TL;
    }

   /*12位精度转换时，TH的低三位和TL的高四位组成温度值的整数部分，    而TL的低四位为小数精度部分,并且精度系数为0.0625 */
    temp = (tmp>>4) + (tmp&0xF)*0.0625 ;

    *temperature = sign ? temp : -temp;

    return 0;
}