SGP30模块测试(51单片机代码)

仅供测试，本人亲测可用。

#include  #include   #define uchar unsigned char #define uint unsigned int #define slave_addr_write 0xb0 #define slave_addr_read 0xb1  sbit scl=P0^2; sbit sda=P0^3; void delay(uint num); void usart_init(); uchar send_sgp30_flag; //起始 void i2c_start() {  sda=1;  delay(5);   scl=1;  delay(5);  sda=0;  delay(5);  scl=0;  delay(5); } //结束 void i2c_stop() {  sda=0;  delay(5);  scl=1;  delay(5);  sda=1;  delay(5);  scl=0;  delay(5); } ///主机响应 void master_ack() {  scl=0;  delay(5);  sda=0;  delay(5);  scl=1;  delay(5);  scl=0;  delay(5);  sda=1;  delay(5); } ///主机不响应 void master_nack() {  sda=1;  delay(5);  scl=0;  delay(5);   scl=1;  delay(5);  scl=0;  delay(5);  sda=0;  delay(5);  sda=1;  delay(5); } //写一个字节 uchar i2c_write_byte(uchar buffer) {  uchar i,j;  for(i=0;i<8;i  )  {   sda=(buffer<200)   {    scl=0;    ES=0;    TI=1;    printf("no ack\n");    while(!TI);    TI=0;    ES=1;    return 0;    }  }  scl=0;  delay(5);  return 1; } ///读一个字节 uchar i2c_read_byte(uchar ack) {  uchar i,temp;  for(i=0;i<8;i  )  {   scl=1;   delay(5);   temp<<=1;         temp|=sda;    delay(5);   scl=0;   delay(5);    }  if(ack)  {   master_ack();  }  else  {   master_nack();  }  return temp;  } //初始化 void init_air_quality() {  i2c_start();  i2c_write_byte(slave_addr_write);   i2c_write_byte(0x20);  i2c_write_byte(0x03);  i2c_stop(); } //开始测量 void measure_air_quality(uint *p) {  uint tvoc,co2;  uchar crc;  i2c_start();  i2c_write_byte(slave_addr_write);  i2c_write_byte(0x20);  i2c_write_byte(0x08);  delay(200);  i2c_start();  i2c_write_byte(slave_addr_read);    co2=i2c_read_byte(1);  co2<<=8;  co2|=i2c_read_byte(1);    crc=i2c_read_byte(1);  *p=co2;  p  ;  tvoc=i2c_read_byte(1);  tvoc<<=8;  tvoc|=i2c_read_byte(1);  crc=i2c_read_byte(0);  *p=tvoc;  i2c_stop();  } void main() {  uint buffer[2];  usart_init();  scl=0;  sda=0;  delay(100);  init_air_quality();  delay(200);  TR0=1;  ES=0;  TI=1;  printf("start! \n");  while(!TI);  TI=0;  ES=1;   measure_air_quality(buffer);  while(1)  {   if(send_sgp30_flag==1)//每隔1s发送一次   {    send_sgp30_flag=0;    measure_air_quality(buffer);    ES=0;    TI=1;    printf("co2 :%u ppm\r\n",buffer[0]);    printf("tvoc:%d ppd\n",buffer[1]);    while(!TI);    TI=0;    ES=1;   }  } } // void usart_init() {  TMOD=0x21;  SCON=0X50;  TH1=0xfd;  TL1=0xfd;  TH0=(65536-45872)/256;  TL0=(65536-45872)%6;  TR0=0;  ET0=1;  TR1=1;  EA=1;  ES=1;  } //1s定时 void time0() interrupt 1 {  uchar i;  TH0=(65536-45872)/256;  TL0=(65536-45872)%6;  i  ;  if(i==20)  {   i=0;   send_sgp30_flag=1;  } } void delay(uint num) {  uchar i,j;  for(i=0;i