/* * Marlin 3D Printer Firmware * Copyright (C) 2016 MarlinFirmware [https://github.com/MarlinFirmware/Marlin] * * Based on Sprinter and grbl. * Copyright (C) 2011 Camiel Gubbels / Erik van der Zalm * * This program is free software: you can redistribute it and/or modify * it under the terms of the GNU General Public License as published by * the Free Software Foundation, either version 3 of the License, or * (at your option) any later version. * * This program is distributed in the hope that it will be useful, * but WITHOUT ANY WARRANTY; without even the implied warranty of * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the * GNU General Public License for more details. * * You should have received a copy of the GNU General Public License * along with this program. If not, see . * */ #ifndef TWIBUS_H #define TWIBUS_H #include "macros.h" #include // Print debug messages with M111 S2 (Uses 236 bytes of PROGMEM) //#define DEBUG_TWIBUS typedef void (*twiSlaveFunc_t)(int bytes); /** * TWIBUS class * * This class implements a wrapper around the two wire (I2C) bus, it allows * Marlin to send and request data from any slave device on the bus. This is * an experimental feature and it's inner workings as well as public facing * interface are prune to change in the future. * * The two main consumers of this class are M155 and M156, where M155 allows * Marlin to send a I2C packet to a device (please be aware that no repeated * starts are possible), this can be done in caching method by calling multiple * times M155 B or a one liner M155, have a look at * the gcode_M155() function for more information. M156 allows Marlin to * request data from a device, the received data is then relayed into the serial * line for host interpretation. * */ class TWIBus { private: /** * @brief Timeout value in milliseconds * @details Maximum amount of time (ms) to wait for a reply. * Useful if something goes wrong on the bus and the * SDA/SCL lines are held up by another device. */ const int timeout = 5; /** * @brief Number of bytes on buffer * @description Number of bytes in the buffer waiting to be flushed to the bus. */ uint8_t buffer_s = 0; /** * @brief Internal buffer * @details A fixed buffer. TWI commands can be no longer than this. */ char buffer[32]; public: /** * @brief Target device address * @description The target device address. Persists until changed. */ uint8_t addr = 0; /** * @brief Class constructor * @details Initialize the TWI bus and clear the buffer */ TWIBus(); /** * @brief Reset the buffer * @details Set the buffer to a known-empty state */ void reset(); /** * @brief Send the buffer data to the bus * @details Flush the buffer to the bus at the target address. */ void send(); /** * @brief Add one byte to the buffer * @details Add a byte to the end of the buffer. * Silently fails if the buffer is full. * * @param c a data byte */ void addbyte(const char c); /** * @brief Set the target slave address * @details The target slave address for sending the full packet. * * @param addr 7-bit integer address */ void address(const uint8_t addr); /** * @brief Request data from the slave device * @details Request a number of bytes from a slave device. * This implementation simply sends the data to serial * in a parser-friendly format. * * @param bytes the number of bytes to request */ void reqbytes(const uint8_t bytes); /** * @brief Relay data from the slave device to serial * @details Relay a number of bytes from the bus to * serial in a parser-friendly format. * * @param bytes the number of bytes to request */ void relaydata(uint8_t bytes); #if I2C_SLAVE_ADDRESS > 0 /** * @brief Receive bytes (passively) * @details Receive bytes sent to our slave address. * and simply echo them to serial. */ inline void receive(uint8_t bytes) { relaydata(bytes); } /** * @brief Register a slave handler * @details Set a handler to receive data from the bus, * so we can act as a slave. * * @param handler A function to handle receiving bytes */ inline void onReceive(const twiSlaveFunc_t handler) { Wire.onReceive(handler); } #endif #if ENABLED(DEBUG_TWIBUS) /** * @brief Prints a debug message * @details Prints a simple debug message "TWIBus::function: value" */ static void debug(const char func[], int32_t val = -1); #endif }; #endif //TWIBUS_H