61 lines
1.8 KiB
C
61 lines
1.8 KiB
C
/* Reads LM75 Thermometer and Prints Value over Serial */
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// ------- Preamble -------- //
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#include <avr/io.h>
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#include <util/delay.h>
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#include <avr/power.h>
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#include "pinDefines.h"
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#include "USART.h"
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#include "i2c.h"
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// -------- Defines -------- //
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#define LM75_ADDRESS_W 0b10010000
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#define LM75_ADDRESS_R 0b10010001
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#define LM75_TEMP_REGISTER 0b00000000
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#define LM75_CONFIG_REGISTER 0b00000001
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#define LM75_THYST_REGISTER 0b00000010
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#define LM75_TOS_REGISTER 0b00000011
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// -------- Functions --------- //
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int main(void) {
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uint8_t tempHighByte, tempLowByte;
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// -------- Inits --------- //
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clock_prescale_set(clock_div_1); /* 8MHz */
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initUSART();
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printString("\r\n==== i2c Thermometer ====\r\n");
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initI2C();
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// ------ Event loop ------ //
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while (1) {
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/* To set register, address LM75 in write mode */
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i2cStart();
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i2cSend(LM75_ADDRESS_W);
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i2cSend(LM75_TEMP_REGISTER);
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i2cStart(); /* restart, just send start again */
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/* Setup and send address, with read bit */
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i2cSend(LM75_ADDRESS_R);
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/* Now receive two bytes of temperature */
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tempHighByte = i2cReadAck();
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tempLowByte = i2cReadNoAck();
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i2cStop();
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// Print it out nicely over serial for now...
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printByte(tempHighByte);
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if (tempLowByte & _BV(7)) {
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printString(".5\r\n");
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}
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else {
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printString(".0\r\n");
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}
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/* Once per second */
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_delay_ms(1000);
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} /* End event loop */
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return 0; /* This line is never reached */
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}
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