mirror of
https://github.com/eddyem/stm32samples.git
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106 lines
3.2 KiB
C
106 lines
3.2 KiB
C
/*
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* geany_encoding=koi8-r
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* i2c.c
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*
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* Copyright 2017 Edward V. Emelianov <eddy@sao.ru, edward.emelianoff@gmail.com>
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*
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* This program is free software; you can redistribute it and/or modify
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* it under the terms of the GNU General Public License as published by
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* the Free Software Foundation; either version 2 of the License, or
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* (at your option) any later version.
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*
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* This program is distributed in the hope that it will be useful,
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* but WITHOUT ANY WARRANTY; without even the implied warranty of
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* MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
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* GNU General Public License for more details.
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*
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* You should have received a copy of the GNU General Public License
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* along with this program; if not, write to the Free Software
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* Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston,
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* MA 02110-1301, USA.
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*
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*/
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#include "stm32f0.h"
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#include "hardware.h"
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#include "i2c.h"
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#include "usart.h"
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static uint32_t cntr;
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static uint8_t wri2c(uint8_t byte){
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I2C1->CR2 = byte;// | I2C_CR2_AUTOEND;
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if(byte & 1) I2C1->CR2 |= I2C_CR2_RD_WRN;
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// now start transfer
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I2C1->CR2 |= I2C_CR2_START;
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if(I2C1->ISR & I2C_ISR_RXNE) (void) I2C1->RXDR;
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cntr = Tms;
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while((I2C1->ISR & I2C_ISR_TC) == 0) if(Tms - cntr > I2C_TIMEOUT) return 0;
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if(I2C1->ISR & I2C_ISR_RXNE) (void) I2C1->RXDR;
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I2C1->ICR = 0xff; // clear all error flags
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return 1;
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}
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/**
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* write command byte to I2C
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* @param addr - device address (TSYS01_ADDR0 or TSYS01_ADDR1)
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* @param data - byte to write
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* @return 0 if error
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*/
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uint8_t write_i2c(const uint8_t *commands, uint8_t nbytes){
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uint8_t r = 1;
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cntr = Tms;
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while(I2C1->ISR & I2C_ISR_BUSY) if(Tms - cntr > I2C_TIMEOUT) return 0; // check busy
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cntr = Tms;
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while(I2C1->CR2 & I2C_CR2_START) if(Tms - cntr > I2C_TIMEOUT) return 0; // check start
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for(uint8_t i = 0; i < nbytes; ++i){
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if(!wri2c(commands[i])){
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r = 0;
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break;
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}
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}
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I2C1->CR2 |= I2C_CR2_STOP;
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return r;
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}
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/**
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* read nbytes (0..4) of data from I2C line
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* @return 1 if all OK, 0 if NACK or no device found
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*/
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uint8_t read_i2c(uint8_t command, uint8_t *data){
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cntr = Tms;
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while(I2C1->ISR & I2C_ISR_BUSY) if(Tms - cntr > 5) return 0; // check busy
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cntr = Tms;
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while(I2C1->CR2 & I2C_CR2_START) if(Tms - cntr > 5) return 0; // check start
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// read 1 byte
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if(command & 1){
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I2C1->CR2 = (1<<16) | command | I2C_CR2_RD_WRN;
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}else{
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wri2c(command);
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/*
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I2C1->CR2 = command;
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I2C1->CR2 |= I2C_CR2_START;
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cntr = Tms;
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while((I2C1->ISR & I2C_ISR_TC) == 0) if(Tms - cntr > I2C_TIMEOUT) return 0;
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*/
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I2C1->CR2 = (1<<16) |0xff | I2C_CR2_RD_WRN;
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}
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I2C1->CR2 |= I2C_CR2_START;
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I2C1->CR2 |= I2C_CR2_STOP;
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cntr = Tms;
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while(Tms == cntr);
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/*
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while(!(I2C1->ISR & I2C_ISR_RXNE)){ // wait for data
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if(I2C1->ISR & I2C_ISR_NACKF){
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I2C1->ICR |= I2C_ICR_NACKCF;
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return 0;
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}
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if(Tms - cntr > 5) return 0;
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}
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*/
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if(I2C1->ISR & I2C_ISR_RXNE){
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*data = I2C1->RXDR;
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return 1;
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}
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return 0;
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}
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