Driver for PCF8574 (8-bit I2C GPIO expander)
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165
extras/pcf8574/LICENSE
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165
extras/pcf8574/LICENSE
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GNU LESSER GENERAL PUBLIC LICENSE
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Version 3, 29 June 2007
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Copyright (C) 2007 Free Software Foundation, Inc. <http://fsf.org/>
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Everyone is permitted to copy and distribute verbatim copies
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of this license document, but changing it is not allowed.
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This version of the GNU Lesser General Public License incorporates
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the terms and conditions of version 3 of the GNU General Public
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License, supplemented by the additional permissions listed below.
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0. Additional Definitions.
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As used herein, "this License" refers to version 3 of the GNU Lesser
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General Public License, and the "GNU GPL" refers to version 3 of the GNU
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6. Revised Versions of the GNU Lesser General Public License.
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6
extras/pcf8574/component.mk
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6
extras/pcf8574/component.mk
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# Component makefile for extras/pcf8574
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INC_DIRS += $(pcf8574_ROOT)..
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pcf8574_SRC_DIR = $(pcf8574_ROOT)
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$(eval $(call component_compile_rules,pcf8574))
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68
extras/pcf8574/pcf8574.c
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68
extras/pcf8574/pcf8574.c
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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 Lesser General Public License as published by
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* the Free Software Foundation, either version 3 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 Lesser General Public License for more details.
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*
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* You should have received a copy of the GNU Lesser General Public License
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* along with this program. If not, see <http://www.gnu.org/licenses/>.
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*/
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#include "pcf8574.h"
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#include <i2c/i2c.h>
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uint8_t pcf8574_port_read(uint8_t addr)
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{
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i2c_start();
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uint8_t res = i2c_write((addr << 1) | 1) ? i2c_read(1) : 0;
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i2c_stop();
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return res;
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}
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size_t pcf8574_port_read_buf(uint8_t addr, void *buf, size_t len)
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{
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if (!len || !buf) return 0;
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uint8_t *_buf = (uint8_t *)buf;
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i2c_start();
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if (!i2c_write((addr << 1) | 1)) return 0;
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for (size_t i = 0; i < len; i++)
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*_buf++ = i2c_read(i == len - 1);
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i2c_stop();
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return len;
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}
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size_t pcf8574_port_write_buf(uint8_t addr, void *buf, size_t len)
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{
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if (!len || !buf) return 0;
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uint8_t *_buf = (uint8_t *)buf;
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i2c_start();
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if (!i2c_write(addr << 1)) return 0;
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for (size_t i = 0; i < len; i++)
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i2c_write(*_buf++);
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return len;
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}
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void pcf8574_port_write(uint8_t addr, uint8_t value)
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{
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i2c_start();
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if (i2c_write(addr << 1)) i2c_write(value);
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i2c_stop();
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}
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bool pcf8574_gpio_read(uint8_t addr, uint8_t num)
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{
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return (bool)((pcf8574_port_read(addr) >> num) & 1);
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}
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void pcf8574_gpio_write(uint8_t addr, uint8_t num, bool value)
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{
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uint8_t bit = (uint8_t)value << num;
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uint8_t mask = ~(1 << num);
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pcf8574_port_write (addr, (pcf8574_port_read(addr) & mask) | bit);
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}
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84
extras/pcf8574/pcf8574.h
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84
extras/pcf8574/pcf8574.h
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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 Lesser General Public License as published by
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* the Free Software Foundation, either version 3 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 Lesser General Public License for more details.
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*
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* You should have received a copy of the GNU Lesser General Public License
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* along with this program. If not, see <http://www.gnu.org/licenses/>.
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*/
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/**
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* \file Driver for PCF8574 compartible remote 8-bit I/O expanders for I2C-bus
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*/
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#ifndef PCF8574_PCF8574_H_
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#define PCF8574_PCF8574_H_
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#include <stddef.h>
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#include <stdint.h>
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#include <stdbool.h>
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#ifdef __cplusplus
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extern "C"
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{
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#endif
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/**
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* \brief Read GPIO port value
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* \param addr I2C register address (0b0100<A2><A1><A0> for PCF8574)
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* \return 8-bit GPIO port value
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*/
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uint8_t pcf8574_port_read(uint8_t addr);
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/**
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* \brief Continiously read GPIO port values to buffer
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* @param addr I2C register address (0b0100<A2><A1><A0> for PCF8574)
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* @param buf Target buffer
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* @param len Buffer length
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* @return Number of bytes read
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*/
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size_t pcf8574_port_read_buf(uint8_t addr, void *buf, size_t len);
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/**
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* \brief Write value to GPIO port
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* \param addr I2C register address (0b0100<A2><A1><A0> for PCF8574)
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* \param value GPIO port value
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*/
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void pcf8574_port_write(uint8_t addr, uint8_t value);
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/**
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* \brief Continiously write GPIO values to GPIO port
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* \param addr I2C register address (0b0100<A2><A1><A0> for PCF8574)
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* @param buf Buffer with values
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* @param len Buffer length
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* @return Number of bytes written
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*/
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size_t pcf8574_port_write_buf(uint8_t addr, void *buf, size_t len);
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/**
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* \brief Read input value of a GPIO pin
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* \param addr I2C register address (0b0100<A2><A1><A0> for PCF8574)
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* \param num pin number (0..7)
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* \return GPIO pin value
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*/
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bool pcf8574_gpio_read(uint8_t addr, uint8_t num);
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/**
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* \brief Set GPIO pin output
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* Note it's READ - MODIFY - WRITE operation! Please read PCF8574
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* datasheet first.
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* \param addr I2C register address (0b0100<A2><A1><A0> for PCF8574)
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* \param num pin number (0..7)
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* \param value true for high level
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*/
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void pcf8574_gpio_write(uint8_t addr, uint8_t num, bool value);
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#ifdef __cplusplus
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}
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#endif
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#endif /* PCF8574_PCF8574_H_ */
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