251 lines
7.6 KiB
C++
251 lines
7.6 KiB
C++
/*
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* Marlin 3D Printer Firmware
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* Copyright (C) 2016 MarlinFirmware [https://github.com/MarlinFirmware/Marlin]
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*
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* Based on Sprinter and grbl.
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* Copyright (C) 2011 Camiel Gubbels / Erik van der Zalm
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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 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 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, see <http://www.gnu.org/licenses/>.
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*
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*/
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#ifndef TWIBUS_H
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#define TWIBUS_H
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#include "macros.h"
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#include <Wire.h>
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// Print debug messages with M111 S2 (Uses 236 bytes of PROGMEM)
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//#define DEBUG_TWIBUS
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typedef void (*twiReceiveFunc_t)(int bytes);
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typedef void (*twiRequestFunc_t)();
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#define TWIBUS_BUFFER_SIZE 32
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/**
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* TWIBUS class
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*
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* This class implements a wrapper around the two wire (I2C) bus, it allows
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* Marlin to send and request data from any slave device on the bus. This is
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* an experimental feature and it's inner workings as well as public facing
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* interface are prune to change in the future.
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*
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* The two main consumers of this class are M155 and M156, where M155 allows
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* Marlin to send a I2C packet to a device (please be aware that no repeated
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* starts are possible), this can be done in caching method by calling multiple
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* times M155 B<byte-1 value in base 10> or a one liner M155, have a look at
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* the gcode_M155() function for more information. M156 allows Marlin to
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* request data from a device, the received data is then relayed into the serial
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* line for host interpretation.
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*
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*/
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class TWIBus {
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private:
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/**
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* @brief Timeout value in milliseconds
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* @details Maximum amount of time (ms) to wait for a reply.
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* Useful if something goes wrong on the bus and the
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* SDA/SCL lines are held up by another device.
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*/
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const int timeout = 5;
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/**
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* @brief Number of bytes on buffer
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* @description Number of bytes in the buffer waiting to be flushed to the bus
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*/
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uint8_t buffer_s = 0;
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/**
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* @brief Internal buffer
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* @details A fixed buffer. TWI commands can be no longer than this.
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*/
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char buffer[TWIBUS_BUFFER_SIZE];
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public:
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/**
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* @brief Target device address
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* @description The target device address. Persists until changed.
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*/
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uint8_t addr = 0;
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/**
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* @brief Class constructor
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* @details Initialize the TWI bus and clear the buffer
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*/
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TWIBus();
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/**
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* @brief Reset the buffer
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* @details Set the buffer to a known-empty state
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*/
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void reset();
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/**
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* @brief Send the buffer data to the bus
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* @details Flush the buffer to the target address
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*/
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void send();
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/**
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* @brief Add one byte to the buffer
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* @details Add a byte to the end of the buffer.
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* Silently fails if the buffer is full.
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*
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* @param c a data byte
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*/
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void addbyte(const char c);
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/**
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* @brief Add some bytes to the buffer
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* @details Add bytes to the end of the buffer.
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* Concatenates at the buffer size.
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*
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* @param src source data address
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* @param bytes the number of bytes to add
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*/
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void addbytes(char src[], uint8_t bytes);
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/**
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* @brief Add a null-terminated string to the buffer
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* @details Add bytes to the end of the buffer up to a nul.
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* Concatenates at the buffer size.
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*
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* @param str source string address
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*/
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void addstring(char str[]);
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/**
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* @brief Set the target slave address
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* @details The target slave address for sending the full packet
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*
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* @param adr 7-bit integer address
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*/
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void address(const uint8_t adr);
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/**
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* @brief Prefix for echo to serial
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* @details Echo a label, length, address, and "data:"
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*
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* @param bytes the number of bytes to request
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*/
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static void echoprefix(uint8_t bytes, const char prefix[], uint8_t adr);
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/**
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* @brief Echo data on the bus to serial
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* @details Echo some number of bytes from the bus
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* to serial in a parser-friendly format.
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*
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* @param bytes the number of bytes to request
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*/
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static void echodata(uint8_t bytes, const char prefix[], uint8_t adr);
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/**
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* @brief Echo data in the buffer to serial
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* @details Echo the entire buffer to serial
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* to serial in a parser-friendly format.
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*
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* @param bytes the number of bytes to request
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*/
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void echobuffer(const char prefix[], uint8_t adr);
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/**
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* @brief Request data from the slave device and wait.
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* @details Request a number of bytes from a slave device.
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* Wait for the data to arrive until the timeout
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* interval expires. Return true on success.
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*
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* @param bytes the number of bytes to request
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* @return status of the request: true=success, false=timeout
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*/
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bool request(const uint8_t bytes);
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/**
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* @brief Capture data from the bus into the buffer.
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* @details Capture data after a request has succeeded.
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*
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* @param bytes the number of bytes to request
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* @return the number of bytes captured to the buffer
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*/
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uint8_t capture(char *dst, const uint8_t bytes);
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/**
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* @brief Flush the i2c bus.
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* @details Get all bytes on the bus and throw them away.
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*/
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static void flush();
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/**
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* @brief Request data from the slave device, echo to serial.
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* @details Request a number of bytes from a slave device and output
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* the returned data to serial in a parser-friendly format.
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*
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* @param bytes the number of bytes to request
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*/
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void relay(const uint8_t bytes);
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#if I2C_SLAVE_ADDRESS > 0
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/**
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* @brief Register a slave receive handler
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* @details Set a handler to receive data addressed to us
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*
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* @param handler A function to handle receiving bytes
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*/
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inline void onReceive(const twiReceiveFunc_t handler) { Wire.onReceive(handler); }
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/**
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* @brief Register a slave request handler
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* @details Set a handler to send data requested from us
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*
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* @param handler A function to handle receiving bytes
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*/
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inline void onRequest(const twiRequestFunc_t handler) { Wire.onRequest(handler); }
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/**
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* @brief Default handler to receive
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* @details Receive bytes sent to our slave address
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* and simply echo them to serial.
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*/
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void receive(uint8_t bytes);
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/**
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* @brief Send a reply to the bus
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* @details Send the buffer and clear it.
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* If a string is passed, write it into the buffer first.
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*/
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void reply(char str[]=NULL);
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inline void reply(const char str[]) { this->reply((char*)str); }
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#endif
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#if ENABLED(DEBUG_TWIBUS)
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/**
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* @brief Prints a debug message
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* @details Prints a simple debug message "TWIBus::function: value"
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*/
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static void prefix(const char func[]);
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static void debug(const char func[], uint32_t adr);
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static void debug(const char func[], char c);
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static void debug(const char func[], char adr[]);
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static inline void debug(const char func[], uint8_t v) { debug(func, (uint32_t)v); }
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#endif
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};
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#endif //TWIBUS_H
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