I2C Sensor Arduino outputs 0s? -
i have d6t omron temperature sensor (1x8 array) , trying temperature readings it. however, after debugging , making sure there's no error, can't outputted 0's. here's code, modified example contained in softi2cmaster library github, more information here http://playground.arduino.cc/main/softwarei2clibrary
// simple sketch read out bma020 using softi2c // readout bma020 chip // use low processor speed (you have change baud rate 2400!) // #define i2c_cpufreq (f_cpu/8) #define no_interrupt 1 #define i2c_timeout 1000 #define sda_port portc #define sda_pin 4 #define scl_port portc #define scl_pin 5 #include <softi2cmaster.h> #include <avr/io.h> #define bmaaddr 0x14 float ptat, p0, p1, p2, p3, p4, p5, p6, p7, p8, p9, p10, p11, p12, p13, p14, p15, pec; void cpuslowdown(void) { // slow down processor factor of 8 clkpr = _bv(clkpce); clkpr = _bv(clkps1) | _bv(clkps0); } boolean setcontrolbits(uint8_t cntr) { serial.println(f("soft reset")); if (!i2c_start(bmaaddr | i2c_write)) { serial.println("failed @ write start"); return false; } if (!i2c_write(0x4c)) { serial.println("failed @ write"); return false; } i2c_stop(); return true; } boolean initbma(void) { if (!setcontrolbits(b00000010)) return false;; delay(100); return true; } int readoneval(boolean last) { uint8_t msb, lsb; lsb = i2c_read(false); msb = i2c_read(last); if (last) i2c_stop(); return (float)((msb<<8)|lsb)/64; } boolean readbma(void) { ptat = 0xffff; p0 = 0xffff; p1 = 0xffff; p2 = 0xffff; p3 = 0xffff; p4 = 0xffff; p5 = 0xffff; p6 = 0xffff; p7 = 0xffff; pec= 0xffff; if (!i2c_start(bmaaddr | i2c_write)) return false; if (!i2c_write(0x01)) return false; if (!i2c_rep_start(bmaaddr | i2c_read)) return false; ptat = readoneval(false); p0 = readoneval(false); p1 = readoneval(false); p2 = readoneval(false); p3 = readoneval(false); p4 = readoneval(false); p5 = readoneval(false); p6 = readoneval(false); p7 = readoneval(false); pec = readoneval(true); return true; } //------------------------------------------------------------------------------ void setup(void) { #if i2c_cpufreq == (f_cpu/8) cpuslowdown(); #endif serial.begin(19200); // in case of cpu slow down, change baud rate / 8! if (!initbma()) { serial.println(f("init error")); } } void loop(void){ if (!readbma()) serial.println(f("read error")); serial.print(f("ptat=")); serial.println(ptat); serial.print(f(" p0=")); serial.println(p0); serial.print(f(" p1=")); serial.println(p1); serial.print(f(" p2=")); serial.println(p2); serial.print(f(" p3=")); serial.println(p3); serial.print(f(" p4=")); serial.println(p4); serial.print(f(" p5=")); serial.println(p5); serial.print(f(" p6=")); serial.println(p6); serial.print(f(" p7=")); serial.println(p7); serial.print(f(" pec=")); serial.println(pec); delay(300); } please appreciated :(
i have couple of recommendations.
first, data returned temperature device not sent floating point value - 16-bit signed integer. example, if device senses 25.8 degrees, value 258 (0x0102) device during i2c communications. also, quick scan of code shows in readoneval() routine, typecast return float, function defined return int. typecast doesn't anyway data isn't in format expect. have convert yourself.
you need take time understand temperature sensor , how i2c works. recommend read app note mouser has here. specific device , has examples in c language straightforward. should on right track.