Serial.begin and LCD initialization (+SHT11)

i made sketch sht11 , dump reading on 16x2 lcd, , works fine.
however enable possibility read same values usb/serial. add serial.begin() setup rutine lcd refuse initialize.
am overlooking timing or wrong?

code: [select]


#include <lcd4bit.h>
lcd4bit lcd = lcd4bit(2);   //create 2-line display.
#include <stdlib.h>
#include <math.h>

/*
* sht11 usb (serial)
* anders s. nielsen
*
* example of using arduino board receive data
* sensirion sht11 humidity , temperature sensor.
* arduino board relays data sensor usb port (serial port).
* based on code http://dmgaming.com/
*
*/

// pin assignments
int shtclk=3; // sht11 clock pin connected pin
int shtdata=2; // sht11 data pin connected pin
int boardled=13; // led connected pin (on diecimila) , used signal user
int baudrate=9600; // speed used serial communication

// misc variables
long logtime;
int adccount;
int iobyte;
int ackbit;
unsigned int retval; // return value sht11
int dly;
long mstimer;
uint8_t bitmask;
double temp; // changed float double
double humi; // changed float double
double dewpoint;

// calculation constants based on sht11 data sheet
int   d1 = -40;     // sht11 data sheet @ 5v vdd , celcius operation
float d2 = 0.01;    // sht11 data sheet @ 14bit , celcius operation
int   c1 = -4;      // sht11 data sheet @ 12bit operation
float c2 = 0.0405;  // sht11 data sheet @ 12bit operation
float c3 = -2.8e-6; // sht11 data sheet @ 12bit operation

// function writes byte sht11
void sht_write_byte(void)
{
 pinmode(shtdata, output);
 shiftout(shtdata, shtclk, msbfirst, iobyte);
 pinmode(shtdata, input);
 digitalwrite(shtdata, low);
 digitalwrite(shtclk, low);
 digitalwrite(shtclk, high);
 ackbit = digitalread(shtdata);
 digitalwrite(shtclk, low);
}

int shiftin()
{
 int cwt;
 cwt=0;
 bitmask=128;
 while (bitmask >= 1)
 {
   digitalwrite(shtclk, high);
   cwt = cwt + bitmask * digitalread(shtdata);
   digitalwrite(shtclk, low);
   bitmask=bitmask/2;
 }
 return(cwt);
}

// function reads byte sht11
void sht_read_byte(void)
{
 iobyte = shiftin();
 digitalwrite(shtdata, ackbit);
 pinmode(shtdata, output);
 digitalwrite(shtclk, high);
 digitalwrite(shtclk, low);
 pinmode(shtdata, input);
 digitalwrite(shtdata, low);
}

// function reset sht11
void sht_connection_reset(void)
{
 shiftout(shtdata, shtclk, lsbfirst, 255);
 shiftout(shtdata, shtclk, lsbfirst, 255);
}

void sht_soft_reset(void)
{
 sht_connection_reset();
 iobyte = 30;
 ackbit = 1;
 sht_write_byte();
 delay(15);
}

void sht_wait(void)
{
 delay(5);
 dly = 0;
 while (dly < 600)
 {
   if (digitalread(shtdata) == 0) dly=2600;
   delay(1);
   dly=dly+1;
 }
}

void sht_start(void)
{
 digitalwrite(shtdata, high);
 pinmode(shtdata, output);
 digitalwrite(shtclk, high);
 digitalwrite(shtdata, low);
 digitalwrite(shtclk, low);
 digitalwrite(shtclk, high);
 digitalwrite(shtdata, high);
 digitalwrite(shtclk, low);
}

// function reads data sensor
void sht_measure(int vsvc)
{
 sht_soft_reset();
 sht_start();
 iobyte = vsvc;
 sht_write_byte();
 sht_wait();
 ackbit = 0;
 sht_read_byte();
 int msby;
 msby = iobyte;
 ackbit = 1;
 sht_read_byte();
 retval = msby;
 retval = retval * 0x100;
 retval = retval + iobyte;
 if (retval <= 0) retval = 1;
}

// function can current status of sensor
int sht_get_status(void)
{
 sht_soft_reset();
 sht_start();
 iobyte = 7;
 sht_write_byte();
 sht_wait();
 ackbit = 1;
 sht_read_byte();
 return(iobyte);
}

// heater function can used sensor calibration
void sht_heater(void)
{
 sht_soft_reset();
 sht_start();
 iobyte = 6;
 sht_write_byte();
 iobyte = 4;
 sht_write_byte();
 ackbit = 1;
 sht_read_byte();
 delay(500);
 sht_soft_reset();
 sht_start();
 iobyte = 6;
 sht_write_byte();
 iobyte = 0;
 sht_write_byte();
 ackbit = 1;
 sht_read_byte();
}

//--------------------------------------------------------------------
double calc_dewpoint( double h,double t){
//--------------------------------------------------------------------
// calculates dew point
// input: humidity [%rh], temperature [[ch65533]c]
// output: dew point [[ch65533]c]
float k,dew_point; // local variables
k = (log10(h)-2)/0.4343 + (17.62*t)/(243.12+t);
dew_point = 243.12*k/(17.62-k);
return(dew_point);
}


void printint(long n){
 byte buf[10];  // prints 10 digits  
 byte i=0;
 if(n==0)
   lcd.print('0');
 else{
   if(n < 0){
     lcd.print('-');
     n = -n;
   }
   while(n>0 && <= 10){
     buf[i++] = n % 10;  // n % base
     n /= 10;   // n/= base
   }
   for(; >0; i--)
     lcd.print((char) (buf[i-1] < 10 ? '0' + buf[i-1] : 'a' + buf[i-1] - 10));        
 }
}

void printdouble( double val, byte precision){
 // prints val number of decimal places determine precision
 // precision number 0 6 indicating desired decimial places
 // example: printdouble( 3.1415, 2); // prints 3.14 (two decimal places)

 printint( (long)val);  //prints int part
 if( precision > 0) {
   lcd.print('.'); // print decimal point
   unsigned long frac;
   unsigned long mult = 1;
   byte padding = precision -1;
   while(precision--)
     mult *=10;      
   if(val >= 0)
     frac = (val - int(val)) * mult;
   else
     frac = (int(val)- val ) * mult;
   unsigned long frac1 = frac;
   while( frac1 /= 10 )
     padding--;
   while(  padding--)
     lcd.print('0');
   printint(frac) ;
 }
}


void setup()
{
 //setup serial port
 serial.begin(baudrate); // open serial
 
 // initialize lcd
 lcd.init();
 lcd.clear();

 //digitalwrite(boardled, low);
 //delay(1000);
 lcd.cursorto(1,0);
 delay(50);  

 // initialize sht11
 lcd.printin("initialize sht11");  
 pinmode(shtclk, output); // set pin output
 digitalwrite(shtclk, high); // set pin high
 pinmode(shtdata, output);  // set pin output
 pinmode(boardled, output); // set pin output

 // initialize sensor
 lcd.printin("resetting sht11");
 sht_connection_reset(); // reset sht11 sensor
 lcd.cursorto(2,0);
 lcd.printin("reset done");

 digitalwrite(boardled, high); // light pin13 led
 //delay(1000); // wait 1000 miliseconds
 lcd.cursorto(2,0); // move cursor first space on second line
 lcd.printin("ready start!");
 delay(1000);  // wait 1000 miliseconds
 digitalwrite(boardled, low); // turn pin13 led off (we ready)
 lcd.clear();  // remove visible on display
 lcd.cursorto(1,0);
 lcd.printin(" humitemp v0.2a");
 delay(3000);
 
}

void loop()
{
 mstimer=millis(); // load number of milliseconds since arduino board began running current program mstimer
 if (mstimer <= logtime) // if mstimer lower the last time checked run time reset logtime.
 {
   logtime = 0;
 }
 if (mstimer > (logtime + 1000)) // if program has been running in more 5 sec fetch new readings sensor
 {
   logtime = millis(); // recored current program run time
   digitalwrite(boardled, high); // light pin13 led
   sht_measure(3); // sht11 temperature
   digitalwrite(boardled, low); // turn pin13 led off
   temp = d1+d2*retval; // temperature conversion according sht11 data sheet
   lcd.cursorto(1,0); // move lcd cursor first space on first line
   lcd.printin("t:"); // preload lcd text
   printdouble(temp,1); // display temp in ascii on lcd
   lcd.print(223); // print degree character (223d = 11011111b = cfh)
   lcd.printin("c "); // printed right after temperature (no need calculate position)
   digitalwrite(boardled, high); // light pin13 led
   sht_measure(5); // sht11 humidity
   digitalwrite(boardled, low); // turn pin13 led off
   humi = c1+c2*retval+c3*(retval*retval); // humidity conversion according sht11 data sheet
   lcd.printin("h:"); // preload lcd text
   printdouble(humi,1); // display humi in ascii on lcd
   lcd.printin("%rh "); // printed right after humidity (no need calculate position)
   dewpoint = calc_dewpoint(temp,humi);
   lcd.cursorto(2,0); // move lcd cursor first space on second line
   lcd.printin("dp:"); //
   printdouble(dewpoint,1);
   lcd.print(223); // print degree character (223d = 11011111b = cfh)
   lcd.printin("c "); // printed right after temperature (no need calculate position)
 }
}


thanks in advance.

spelle:

lcd4bit written while ago.  there possibility subtle changes in later arduino code causing problem.  there similar problem between liquidcrystal library , arduino prior v0018.  why don't use arduino v0018 , version of liquidcrystal comes , see if have better luck.

don

Arduino Forum > Forum 2005-2010 (read only) > Software > Interfacing > Serial.begin and LCD initialization (+SHT11)

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