177 lines
4.9 KiB
C
177 lines
4.9 KiB
C
/*
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* The MIT License (MIT)
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*
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* Copyright (c) 2015 Johan Kanflo (github.com/kanflo)
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*
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* Permission is hereby granted, free of charge, to any person obtaining a copy
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* of this software and associated documentation files (the "Software"), to deal
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* in the Software without restriction, including without limitation the rights
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* to use, copy, modify, merge, publish, distribute, sublicense, and/or sell
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* copies of the Software, and to permit persons to whom the Software is
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* furnished to do so, subject to the following conditions:
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*
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* The above copyright notice and this permission notice shall be included in
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* all copies or substantial portions of the Software.
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*
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* THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
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* IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
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* FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE
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* AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER
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* LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM,
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* OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN
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* THE SOFTWARE.
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*/
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#ifndef __I2C_H__
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#define __I2C_H__
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#include <stdint.h>
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#include <stdbool.h>
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#include <errno.h>
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#include <FreeRTOS.h>
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#include <task.h>
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#ifdef __cplusplus
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extern "C" {
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#endif
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/*
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* Define i2c bus max number
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*/
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#define MAX_I2C_BUS 2
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/*
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* following array contain value for different frequency
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* Warning : 1 is minimal, that mean at 80MHz clock, frequency max is 320kHz
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* Array format is { {160MHz, 80MHz} , {160MHz, 80MHz} , ... }
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*/
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#define NB_FREQ_AVAILABLE 4
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typedef enum {
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I2C_FREQ_80K = 0,
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I2C_FREQ_100K,
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I2C_FREQ_400K,
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I2C_FREQ_500K,
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} i2c_freq_t;
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const static uint8_t i2c_freq_array[NB_FREQ_AVAILABLE][2] = { {255,35}, {100,20}, {10,1}, {6,1} } ;
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/**
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* Device descriptor
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*/
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typedef struct i2c_dev {
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uint8_t bus ;
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uint8_t addr ;
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} i2c_dev_t ;
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/**
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* Bus settings
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*/
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typedef struct i2c_bus_description {
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uint8_t g_scl_pin; // Scl pin
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uint8_t g_sda_pin; // Sda pin
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uint8_t frequency; // frequency selection
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bool started;
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bool flag;
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bool force;
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} i2c_bus_description_t ;
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// I2C driver for ESP8266 written for use with esp-open-rtos
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// Based on https://en.wikipedia.org/wiki/I²C#Example_of_bit-banging_the_I.C2.B2C_Master_protocol
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// With calling overhead, we end up at ~320kbit/s
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//Level 0 API
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/**
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* Init bitbanging I2C driver on given pins
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* @param bus Bus i2c selection
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* @param scl_pin SCL pin for I2C
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* @param sda_pin SDA pin for I2C
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* @param freq frequency of bus (ex : I2C_FREQ_400K)
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*/
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void i2c_init(uint8_t bus, uint8_t scl_pin, uint8_t sda_pin, i2c_freq_t freq);
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/**
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* Change bus frequency
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* @param bus Bus i2c selection
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* @param freq frequency of bus (ex : I2C_FREQ_400K)
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*/
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void i2c_frequency(uint8_t bus, i2c_freq_t freq);
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/**
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* Write a byte to I2C bus.
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* @param bus Bus i2c selection
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* @param byte Pointer to device descriptor
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* @return true if slave acked
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*/
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bool i2c_write(uint8_t bus, uint8_t byte);
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/**
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* Read a byte from I2C bus.
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* @param bus Bus i2c selection
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* @param ack Set Ack for slave (false: Ack // true: NoAck)
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* @return byte read from slave.
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*/
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uint8_t i2c_read(uint8_t bus, bool ack);
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/**
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* Send start or restart condition
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* @param bus Bus i2c selection
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*/
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void i2c_start(uint8_t bus);
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/**
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* Send stop condition
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* @param bus Bus i2c selection
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* @return false if link was broken
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*/
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bool i2c_stop(uint8_t bus);
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/**
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* get status from I2C bus.
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* @param bus Bus i2c selection
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* @return true if busy.
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*/
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bool i2c_status(uint8_t bus);
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//Level 1 API (Don't need functions above)
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/**
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* This function will allow you to force a transmission I2C, cancel current transmission.
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* Warning: Use with precaution. Don't use it if you can avoid it. Usefull for priority transmission.
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* @param bus Bus i2c selection
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* @param state Force the next I2C transmission if true (Use with precaution)
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*/
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void i2c_force_bus(uint8_t bus, bool state);
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/**
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* Write 'len' bytes from 'buf' to slave at 'data' register adress .
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* @param bus Bus i2c selection
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* @param slave_addr slave device address
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* @param data Pointer to register address to send if non-null
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* @param buf Pointer to data buffer
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* @param len Number of byte to send
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* @return Non-Zero if error occured
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*/
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int i2c_slave_write(uint8_t bus, uint8_t slave_addr, const uint8_t *data, const uint8_t *buf, uint32_t len);
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/**
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* Issue a send operation of 'data' register adress, followed by reading 'len' bytes
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* from slave into 'buf'.
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* @param bus Bus i2c selection
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* @param slave_addr slave device address
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* @param data Pointer to register address to send if non-null
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* @param buf Pointer to data buffer
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* @param len Number of byte to read
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* @return Non-Zero if error occured
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*/
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int i2c_slave_read(uint8_t bus, uint8_t slave_addr, const uint8_t *data, uint8_t *buf, uint32_t len);
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#ifdef __cplusplus
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}
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#endif
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#endif /* __I2C_H__ */
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