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166 lines
3.3 KiB
166 lines
3.3 KiB
/**
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* ---------------------------------------------------------------+
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* @desc Two Wire Interface / I2C Communication
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* ---------------------------------------------------------------+
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* Copyright (C) 2020 Marian Hrinko.
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* Written by Marian Hrinko (mato.hrinko@gmail.com)
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*
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* @author Marian Hrinko
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* @datum 06.09.2020
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* @file twi.c
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* @tested AVR Atmega16, ATmega8, Atmega328
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*
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* @depend
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* ---------------------------------------------------------------+
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* @usage Master Transmit Operation
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*/
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// include libraries
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#include <avr/io.h>
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#include "twi.h"
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/**
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* @desc TWI init - initialize frequency
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*
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* @param void
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*
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* @return void
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*/
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void TWI_Init (void)
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{
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// +++++++++++++++++++++++++++++++++++++++++++++
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// Calculation fclk:
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//
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// fclk = (fcpu)/(16+2*TWBR*4^Prescaler)
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// ---------------------------------------------
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// Calculation TWBR:
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//
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// TWBR = {(fcpu/fclk) - 16 } / (2*4^Prescaler)
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// +++++++++++++++++++++++++++++++++++++++++++++
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// @param1 value of TWBR,
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// fclk = 400kHz (m16); TWBR = 3
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// fclk = 100kHz (m16); TWBR = 20
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// @param2 value of Prescaler = 1
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TWI_FREQ (3, 1);
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}
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/**
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* @desc TWI MT Start
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*
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* @param void
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*
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* @return char
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*/
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char TWI_MT_Start (void)
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{
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// null status flag
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TWI_TWSR &= ~0xA8;
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// START
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// ----------------------------------------------
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// request for bus
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TWI_START();
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// wait till flag set
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TWI_WAIT_TILL_TWINT_IS_SET();
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// test if start or repeated start acknowledged
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if ((TWI_STATUS != TWI_START_ACK) && (TWI_STATUS != TWI_REP_START_ACK)) {
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// return status
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return TWI_STATUS;
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}
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// success
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return SUCCESS;
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}
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/**
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* @desc TWI Send address + write
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*
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* @param char
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*
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* @return char
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*/
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char TWI_MT_Send_SLAW (char address)
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{
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// SLA+W
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// ----------------------------------------------
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TWI_TWDR = (address << 1);
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// enable
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TWI_ENABLE();
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// wait till flag set
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TWI_WAIT_TILL_TWINT_IS_SET();
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// test if SLA with WRITE acknowledged
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if (TWI_STATUS != TWI_MT_SLAW_ACK) {
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// return status
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return TWI_STATUS;
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}
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// success
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return SUCCESS;
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}
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/**
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* @desc TWI Send data
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*
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* @param char
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*
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* @return char
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*/
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char TWI_MT_Send_Data (char data)
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{
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// DATA
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// ----------------------------------------------
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TWI_TWDR = data;
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// enable
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TWI_ENABLE();
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// wait till flag set
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TWI_WAIT_TILL_TWINT_IS_SET();
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// test if data acknowledged
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if (TWI_STATUS != TWI_MT_DATA_ACK) {
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// return status
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return TWI_STATUS;
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}
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// success
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return SUCCESS;
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}
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/**
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* @desc TWI Send address + read
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*
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* @param char
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*
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* @return char
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*/
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char TWI_MR_Send_SLAR (char address)
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{
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// SLA+R
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// ----------------------------------------------
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TWI_TWDR = (address << 1) | 0x01;
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// enable
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TWI_ENABLE();
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// wait till flag set
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TWI_WAIT_TILL_TWINT_IS_SET();
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// test if SLA with READ acknowledged
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if (TWI_STATUS != TWI_MR_SLAR_ACK) {
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// return status
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return TWI_STATUS;
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}
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// success
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return SUCCESS;
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}
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/**
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* @desc TWI stop
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*
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* @param void
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*
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* @return void
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*/
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void TWI_Stop (void)
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{
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// End TWI
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// -------------------------------------------------
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// send stop sequence
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TWI_STOP ();
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// wait for TWINT flag is set
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// TWI_WAIT_TILL_TWINT_IS_SET();
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}
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