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CCS Pic C ile SHT XX serisi kullanimi.

Merhaba sevgili okurlarim bir arkadasimi projesinde kullanmak uzere SHT11 isi ve nem sensorunun kodlarina ihtiyac duymustum cok guzel bir c dosyasina ulastim ve sizinle de paylasmak istedim. Proje bittiginde sitemde yayinlamaktan guru duyacagim cihazin hazir sinifi su sekildedir.

benim sht11.c dosyam

///////////////////////////////////////////////////////////////////////////////
//                                                                           //
// Driver file for SHT75 Temperature & Humidity Sensor                       //
//                                                                           //
// ***** To initialise SHT75 sensor upon power up *****                      //
//                                                                           //
// Function : sht_init()                                                     //
// Return   : none                                                           //
//                                                                           //
//                                                                           //
// ***** To measure and caluculate SHT75 temp & real RH *****                //
//                                                                           //
// Function : sht_rd (temp, truehumid)                                       //
// Return   : temperature & true humidity in float values                    //
//                                                                           //
/////////////////////////////////////////////////////////////////////////////// 

#define sht_data_pin   PIN_D7
#define sht_clk_pin    PIN_D6 

//***** Function to alert SHT75 ***** 

void comstart (void)
{
 output_float(sht_data_pin);  //data high
 output_bit(sht_clk_pin, 0);  //clk low
 delay_us(1);
 output_bit(sht_clk_pin, 1);  //clk high
 delay_us(1);
 output_bit(sht_data_pin, 0); //data low
 delay_us(1);
 output_bit(sht_clk_pin, 0);  //clk low
 delay_us(2);
 output_bit(sht_clk_pin, 1);  //clk high
 delay_us(1);
 output_float(sht_data_pin);  //data high
 delay_us(1);
 output_bit(sht_clk_pin, 0);  //clk low
} 

//***** Function to write data to SHT75 ***** 

int1 comwrite (int8 iobyte)
{
 int8 i, mask = 0x80;
 int1 ack; 

 //Shift out command
 delay_us(4);
 for(i=0; i<8; i++)
  {
   output_bit(sht_clk_pin, 0);                          //clk low
   if((iobyte & mask) > 0) output_float(sht_data_pin);  //data high if MSB high
   else output_bit(sht_data_pin, 0);                    //data low if MSB low
   delay_us(1);
   output_bit(sht_clk_pin, 1);                          //clk high
   delay_us(1);
   mask = mask >> 1;                                    //shift to next bit
  } 

 //Shift in ack
 output_bit(sht_clk_pin, 0);  //clk low
 delay_us(1);
 ack = input(sht_data_pin);   //get ack bit
 output_bit(sht_clk_pin, 1);  //clk high
 delay_us(1);
 output_bit(sht_clk_pin, 0);  //clk low
 return(ack);
} 

//***** Function to read data from SHT75 ***** 

int16 comread (void)
{
 int8 i;
 int16 iobyte = 0;
 const int16 mask0 = 0x0000;
 const int16 mask1 = 0x0001; 

 //shift in MSB data
 for(i=0; i<8; i++)
  {
   iobyte = iobyte << 1;
   output_bit(sht_clk_pin, 1);                //clk high
   delay_us(1);
   if (input(sht_data_pin)) iobyte |= mask1;  //shift in data bit
   else iobyte |= mask0;
   output_bit(sht_clk_pin, 0);                //clk low
   delay_us(1);
  } 

 //send ack 0 bit
 output_bit(sht_data_pin, 0); //data low
 delay_us(1);
 output_bit(sht_clk_pin, 1);  //clk high
 delay_us(2);
 output_bit(sht_clk_pin, 0);  //clk low
 delay_us(1);
 output_float(sht_data_pin);  //data high 

 //shift in LSB data
 for(i=0; i<8; i++)
  {
   iobyte = iobyte << 1;
   output_bit(sht_clk_pin, 1);                //clk high
   delay_us(1);
   if (input(sht_data_pin)) iobyte |= mask1;  //shift in data bit
   else iobyte |= mask0;
   output_bit(sht_clk_pin, 0);                //clk low
   delay_us(1);
  } 

 //send ack 1 bit
 output_float(sht_data_pin);  //data high
 delay_us(1);
 output_bit(sht_clk_pin, 1);  //clk high
 delay_us(2);
 output_bit(sht_clk_pin, 0);  //clk low 

 return(iobyte);
} 

//***** Function to wait for SHT75 reading ***** 

void comwait (void)
{
 int16 sht_delay; 

 output_float(sht_data_pin);                     //data high
 output_bit(sht_clk_pin, 0);                     //clk low
 delay_us(1);
 for(sht_delay=0; sht_delay<30000; sht_delay++)  // wait for max 300ms
  {
   if (!input(sht_data_pin)) break;              //if sht_data_pin low, SHT75 ready
   delay_us(10);
  }
} 

//***** Function to reset SHT75 communication ***** 

void comreset (void)
{
 int8 i; 

 output_float(sht_data_pin);    //data high
 output_bit(sht_clk_pin, 0);    //clk low
 delay_us(2);
 for(i=0; i<9; i++)
  {
   output_bit(sht_clk_pin, 1);  //toggle clk 9 times
   delay_us(2);
   output_bit(sht_clk_pin, 0);
   delay_us(2);
 }
 comstart();
} 

//***** Function to soft reset SHT75 ***** 

void sht_soft_reset (void)
{
 comreset();           //SHT75 communication reset
 comwrite(0x1e);       //send SHT75 reset command
 delay_ms(15);         //pause 15 ms
} 

//***** Function to measure SHT75 temperature ***** 

int16 measuretemp (void)
{
 int1 ack;
 int16 iobyte; 

 comstart();             //alert SHT75
 ack = comwrite(0x03);   //send measure temp command and read ack status
 if(ack == 1) return;
 comwait();              //wait for SHT75 measurement to complete
 iobyte = comread();     //read SHT75 temp data
 return(iobyte);
} 

//***** Function to measure SHT75 RH ***** 

int16 measurehumid (void)
{
 int1 ack;
 int16 iobyte; 

 comstart();            //alert SHT75
 ack = comwrite(0x05);  //send measure RH command and read ack status
 if(ack == 1) return;
 comwait();             //wait for SHT75 measurement to complete
 iobyte = comread();    //read SHT75 temp data
 return(iobyte);
} 

//***** Function to calculate SHT75 temp & RH ***** 

void calculate_data (int16 temp, int16 humid, float & tc, float & rhlin, float & rhtrue)
{
 float truehumid1, rh; 

 //calculate temperature reading
 tc = ((float) temp * 0.01) - 40.0; 

 //calculate Real RH reading
 rh = (float) humid; 

 rhlin = (rh * 0.0405) - (rh * rh * 0.0000028) - 4.0; 

 //calculate True RH reading
 rhtrue = ((tc - 25.0) * (0.01 + (0.00008 * rh))) + rhlin;
} 

//***** Function to measure & calculate SHT75 temp & RH ***** 

void sht_rd (float & temp, float & truehumid)
{
 int16 restemp, reshumid;
 float realhumid;
 restemp = 0; truehumid = 0; 

 restemp = measuretemp();    //measure temp
 reshumid = measurehumid();  //measure RH
calculate_data (restemp, reshumid, temp, realhumid, truehumid);  //calculate temp & RH
} 

//***** Function to initialise SHT75 on power-up ***** 

void sht_init (void)
{
 comreset();    //reset SHT75
 delay_ms(20);  //delay for power-up
}

SHT75.C olarak internette geciyor; orjinal olarak SHT75 icin yazilmis olsada SHT11, SHT71 ve SHT15 ilede sorunsuz calisiyor.

PIC16F877 icin ornek kodu asagidaki sekildedir:

#include <16F877A.h>
#fuses HS,NOWDT,PUT,NOPROTECT,NOLVP
#use delay(clock=20000000) 

#include<lcd.c>
#include<sht75.c> 

void main()
{
 float restemp, truehumid;
 lcd_init();
 sht_init(); 

 while(1)
 {
  sht_rd (restemp, truehumid);
  lcd_gotoxy(1,1);
  printf(lcd_putc, "Temp : %3.1f %cC   ", restemp, 223);
  printf(lcd_putc, "\nRH   : %3.1f %%   ", truehumid);
  delay_ms(500);        //delay 500 ms between reading to prevent self heating of sensor
 }
}

bu kodlarin orjinal hali CCS PIC C  forumlarinda mevcuttur. benim kullanmakta oldum expkits urunu olan EX8B2 pic gelistirme bordunda bu kodlari kullanacak olursaniz degistirmeniz gereken bazi bolumler mevcut.

ilk degistirmeniz gereken bolum SHT75.c dosyasinda bulunan

#define sht_data_pin   PIN_D7
#define sht_clk_pin    PIN_D6

bolumunu kendi data pinimiz ve clock sinyali pinimiz olan C4; C3 ile degistirmeliyiz.

#define sht_data_pin   PIN_C4
#define sht_clk_pin    PIN_C3

bundan sonraki adimda ise expkitsin LCD data gondermede kullandigi exLCD.c dosyasi ile normal ccs pic cnin LCD.C dosyasi farklidir.
(Bunun expkits bordunun LCD cikisi default portta kullanilmiyim portB ile calismasi icin modifiye edilmis olmasidir)

yani uzun lafin kisasi

#include<lcd.c>

satirini

#include<exlcd.c>

olarak degistirdiginizde yazilimsal olarak expkits'de kullanima hazirsiniz.

DIKKAT : Kullanim esnasinda sorun yasamamaniz icin asagidaki maddelere dikkat ediniz.

1. SHT sensorunuz bordun uzerine dogru polarize edilecek sekilde takilmalidir.
   (normalde algiliyici yukari bakacak sekilde; ama GND ve VCC nin yerini kontrol etmeniz daha dogru olur)
2. SWDIP7 deki SDA ve SCK nin ON konumunda olduguna dikkat ediniz.
3. Expkits bordunuzun C4 ve C3 PINlerinin PULL DOWN olarak tanimlarsaniz (Normalde 1 basinca 0 olacak sekilde) sorunsuz olcum yaparsiniz.
   (Bu adimi atlarsaniz ISI -40, -39 gibi bir sey gosteriyor olacaktir.)