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ShimkoMax

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  1. Здравствуйте. Требуется вывести данные температуры и влажности на экран. С LCD дисплеем разобрался, осталось разобраться с SHT21. Постоянно выводит 0 на дисплей: Main.c: #define F_CPU 8000000UL #include <avr/io.h> #include <avr/interrupt.h> #include <util/delay.h> #include <stdio.h> #include <stdlib.h> #include "globals.h" #include "LCD_lib.h" #include "twi.h" // I2C #include "sht21.h" int main(void) { I2C_Init(); _delay_ms(100); LCD_init(); char buffer[20]; roomAdrInit(); SHT21_reset(); while(1) { SHT21_reset(); LCD_sendString(itoa((int)get_temperature(), buffer, 10), 4, 0, 0); _delay_ms(1000); } } twi.c: #include#inclu <avr/io.h> #include "twi.h" void I2C_Init(void) { TWSR = 0; TWBR = 0x20; TWCR = (1<<TWINT) | (1<<TWSTA) | (1<<TWEN); } void I2C_StartCondition(void) { TWCR = (1<<TWINT)|(1<<TWSTA)|(1<<TWEN); while(!(TWCR & (1<<TWINT))); } void I2C_StopCondition(void) { TWCR = (1<<TWINT)|(1<<TWSTO)|(1<<TWEN); } void I2C_SendByte(uint8_t data) { TWDR = data; TWCR = (1<<TWINT) | (1<<TWEN); while(!(TWCR & (1<<TWINT))); } unsigned char I2C_ReadByteAck(void) { TWCR = (1<<TWINT) | (1<<TWEN) | (1<<TWEA); while(!(TWCR & (1<<TWINT))); return TWDR; } unsigned char I2C_ReadByteNak(void) { TWCR = (1<<TWINT) | (1<<TWEN); while(!(TWCR & (1<<TWINT))); return TWDR; } sht21.c: #define F_CPU 8000000UL #include <avr/io.h> #include <util/delay.h> #include <stdlib.h> #include <stdio.h> #include "twi.h" #include "sht21.h" void SHT21_reset() { unsigned char reg[1]; reg[0]=SHT21_reset_cmd; I2C_StartCondition(); I2C_SendByte(SHT21_i2c_write); I2C_SendByte(*reg); I2C_StopCondition(); _delay_ms(100); } uint16_t checksum(unsigned char data[],uint8_t byte, uint8_t check) { uint8_t crc=0; uint8_t bytectr,bit; for (bytectr=0; bytectr<byte;bytectr++) { crc^=(data[bytectr]); for (bit=8;bit>0;bit--) { if(crc&0x80) { crc=(crc<<1)^polynomial; } else { crc=crc<<1; } } } if (crc!=check) { return 0; } else { return data; } } void write_user_register() { unsigned char reg[3]; reg[0]=user_register_write; reg[1]=0x44; I2C_StartCondition(); I2C_SendByte(SHT21_i2c_write); I2C_SendByte(*reg); I2C_StopCondition(); } uint16_t read_value(uint8_t reg) { char data[4],crc; uint16_t result; data[0]=reg; I2C_StartCondition(); I2C_SendByte(SHT21_i2c_write); I2C_SendByte(reg); I2C_StartCondition(); I2C_SendByte(SHT21_i2c_read); data[1] = I2C_ReadByteAck(); data[2] = I2C_ReadByteAck(); crc=I2C_ReadByteNak(); I2C_StopCondition(); result=(data[1]<<8) | data[2]; checksum(result,4,crc); result &= 0xFFFC; return result; } float get_humidity() { //char buffer2[4]; uint16_t hum_value = read_value(humidity_hold_mode); return -6 + 125.0 / 65536.0 * hum_value; //dtostrf(rh,5,2,buffer2); _delay_ms(100); } float get_temperature() { //char buffer1[4]; uint16_t temp_value = read_value(temperature_hold_mode); return -46.85 + 175.72 / 65536.0 * temp_value; //dtostrf(tc,5,2,buffer1); _delay_ms(100); }