From 2521c1e907f21b42bbf4fc626ea9b503f9b3fa7b Mon Sep 17 00:00:00 2001 From: Ivan Grokhotkov Date: Tue, 9 Dec 2014 10:11:42 +0300 Subject: [PATCH] Wire library with i2c master support --- libraries/Wire/Wire.cpp | 311 ++++++++++++++++ libraries/Wire/Wire.h | 86 +++++ libraries/Wire/keywords.txt | 32 ++ libraries/Wire/library.properties | 8 + libraries/Wire/utility/i2c.c | 175 +++++++++ libraries/Wire/utility/i2c.cpp | 214 +++++++++++ libraries/Wire/utility/i2c.h | 27 ++ libraries/Wire/utility/twi.c.unused | 527 ++++++++++++++++++++++++++++ libraries/Wire/utility/twi.h | 53 +++ 9 files changed, 1433 insertions(+) create mode 100644 libraries/Wire/Wire.cpp create mode 100644 libraries/Wire/Wire.h create mode 100644 libraries/Wire/keywords.txt create mode 100644 libraries/Wire/library.properties create mode 100644 libraries/Wire/utility/i2c.c create mode 100644 libraries/Wire/utility/i2c.cpp create mode 100644 libraries/Wire/utility/i2c.h create mode 100644 libraries/Wire/utility/twi.c.unused create mode 100644 libraries/Wire/utility/twi.h diff --git a/libraries/Wire/Wire.cpp b/libraries/Wire/Wire.cpp new file mode 100644 index 000000000..633ecaed2 --- /dev/null +++ b/libraries/Wire/Wire.cpp @@ -0,0 +1,311 @@ +/* + TwoWire.cpp - TWI/I2C library for Wiring & Arduino + Copyright (c) 2006 Nicholas Zambetti. All right reserved. + + This library is free software; you can redistribute it and/or + modify it under the terms of the GNU Lesser General Public + License as published by the Free Software Foundation; either + version 2.1 of the License, or (at your option) any later version. + + This library 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 + Lesser General Public License for more details. + + You should have received a copy of the GNU Lesser General Public + License along with this library; if not, write to the Free Software + Foundation, Inc., 51 Franklin St, Fifth Floor, Boston, MA 02110-1301 USA + + Modified 2012 by Todd Krein (todd@krein.org) to implement repeated starts +*/ + +extern "C" { + #include + #include + #include +} + +#include "i2c.h" +#include "Wire.h" + +// Initialize Class Variables ////////////////////////////////////////////////// + +uint8_t TwoWire::rxBuffer[BUFFER_LENGTH]; +uint8_t TwoWire::rxBufferIndex = 0; +uint8_t TwoWire::rxBufferLength = 0; + +uint8_t TwoWire::txAddress = 0; +uint8_t TwoWire::txBuffer[BUFFER_LENGTH]; +uint8_t TwoWire::txBufferIndex = 0; +uint8_t TwoWire::txBufferLength = 0; + +uint8_t TwoWire::transmitting = 0; +void (*TwoWire::user_onRequest)(void); +void (*TwoWire::user_onReceive)(int); + +// Constructors //////////////////////////////////////////////////////////////// + +TwoWire::TwoWire() +{ +} + +// Public Methods ////////////////////////////////////////////////////////////// + +void TwoWire::pins(int sda, int scl) +{ + i2c_init(sda, scl); +} + +void TwoWire::begin(void) +{ + rxBufferIndex = 0; + rxBufferLength = 0; + + txBufferIndex = 0; + txBufferLength = 0; + +} + +void TwoWire::begin(uint8_t address) +{ + // twi_setAddress(address); + // twi_attachSlaveTxEvent(onRequestService); + // twi_attachSlaveRxEvent(onReceiveService); + // begin(); +} + +void TwoWire::begin(int address) +{ + // begin((uint8_t)address); +} + +void TwoWire::setClock(uint32_t frequency) +{ + i2c_freq(frequency); +} +size_t TwoWire::requestFrom(uint8_t address, size_t size, bool sendStop) +{ + // clamp to buffer length + if(size > BUFFER_LENGTH){ + size = BUFFER_LENGTH; + } + // perform blocking read into buffer + size_t read = i2c_master_read_from(address, rxBuffer, size, sendStop); + // set rx buffer iterator vars + rxBufferIndex = 0; + rxBufferLength = read; + + return read; +} + +uint8_t TwoWire::requestFrom(uint8_t address, uint8_t quantity, uint8_t sendStop) +{ + return requestFrom(address, static_cast(quantity), static_cast(sendStop)); +} + +uint8_t TwoWire::requestFrom(uint8_t address, uint8_t quantity) +{ + return requestFrom(address, static_cast(quantity), true); +} + +uint8_t TwoWire::requestFrom(int address, int quantity) +{ + return requestFrom(static_cast(address), static_cast(quantity), true); +} + +uint8_t TwoWire::requestFrom(int address, int quantity, int sendStop) +{ + return requestFrom(static_cast(address), static_cast(quantity), static_cast(sendStop)); +} + +void TwoWire::beginTransmission(uint8_t address) +{ + // indicate that we are transmitting + transmitting = 1; + // set address of targeted slave + txAddress = address; + // reset tx buffer iterator vars + txBufferIndex = 0; + txBufferLength = 0; +} + +void TwoWire::beginTransmission(int address) +{ + beginTransmission((uint8_t)address); +} + +// +// Originally, 'endTransmission' was an f(void) function. +// It has been modified to take one parameter indicating +// whether or not a STOP should be performed on the bus. +// Calling endTransmission(false) allows a sketch to +// perform a repeated start. +// +// WARNING: Nothing in the library keeps track of whether +// the bus tenure has been properly ended with a STOP. It +// is very possible to leave the bus in a hung state if +// no call to endTransmission(true) is made. Some I2C +// devices will behave oddly if they do not see a STOP. +// +uint8_t TwoWire::endTransmission(uint8_t sendStop) +{ + // transmit buffer (blocking) + int8_t ret = i2c_master_write_to(txAddress, txBuffer, txBufferLength, sendStop); + // reset tx buffer iterator vars + txBufferIndex = 0; + txBufferLength = 0; + // indicate that we are done transmitting + transmitting = 0; + return ret; +} + +// This provides backwards compatibility with the original +// definition, and expected behaviour, of endTransmission +// +uint8_t TwoWire::endTransmission(void) +{ + return endTransmission(true); +} + +// must be called in: +// slave tx event callback +// or after beginTransmission(address) +size_t TwoWire::write(uint8_t data) +{ + if(transmitting){ + // in master transmitter mode + // don't bother if buffer is full + if(txBufferLength >= BUFFER_LENGTH){ + setWriteError(); + return 0; + } + // put byte in tx buffer + txBuffer[txBufferIndex] = data; + ++txBufferIndex; + // update amount in buffer + txBufferLength = txBufferIndex; + }else{ + // in slave send mode + // reply to master + // i2c_slave_transmit(&data, 1); + } + return 1; +} + +// must be called in: +// slave tx event callback +// or after beginTransmission(address) +size_t TwoWire::write(const uint8_t *data, size_t quantity) +{ + if(transmitting){ + // in master transmitter mode + for(size_t i = 0; i < quantity; ++i){ + write(data[i]); + } + }else{ + // in slave send mode + // reply to master + // i2c_slave_transmit(data, quantity); + } + return quantity; +} + +// must be called in: +// slave rx event callback +// or after requestFrom(address, numBytes) +int TwoWire::available(void) +{ + return rxBufferLength - rxBufferIndex; +} + +// must be called in: +// slave rx event callback +// or after requestFrom(address, numBytes) +int TwoWire::read(void) +{ + int value = -1; + + // get each successive byte on each call + if(rxBufferIndex < rxBufferLength){ + value = rxBuffer[rxBufferIndex]; + ++rxBufferIndex; + } + + return value; +} + +// must be called in: +// slave rx event callback +// or after requestFrom(address, numBytes) +int TwoWire::peek(void) +{ + int value = -1; + + if(rxBufferIndex < rxBufferLength){ + value = rxBuffer[rxBufferIndex]; + } + + return value; +} + +void TwoWire::flush(void) +{ + // XXX: to be implemented. +} + +// behind the scenes function that is called when data is received +void TwoWire::onReceiveService(uint8_t* inBytes, int numBytes) +{ + // don't bother if user hasn't registered a callback + // if(!user_onReceive){ + // return; + // } + // // don't bother if rx buffer is in use by a master requestFrom() op + // // i know this drops data, but it allows for slight stupidity + // // meaning, they may not have read all the master requestFrom() data yet + // if(rxBufferIndex < rxBufferLength){ + // return; + // } + // // copy twi rx buffer into local read buffer + // // this enables new reads to happen in parallel + // for(uint8_t i = 0; i < numBytes; ++i){ + // rxBuffer[i] = inBytes[i]; + // } + // // set rx iterator vars + // rxBufferIndex = 0; + // rxBufferLength = numBytes; + // // alert user program + // user_onReceive(numBytes); +} + +// behind the scenes function that is called when data is requested +void TwoWire::onRequestService(void) +{ + // // don't bother if user hasn't registered a callback + // if(!user_onRequest){ + // return; + // } + // // reset tx buffer iterator vars + // // !!! this will kill any pending pre-master sendTo() activity + // txBufferIndex = 0; + // txBufferLength = 0; + // // alert user program + // user_onRequest(); +} + +// sets function called on slave write +void TwoWire::onReceive( void (*function)(int) ) +{ + // user_onReceive = function; +} + +// sets function called on slave read +void TwoWire::onRequest( void (*function)(void) ) +{ + // user_onRequest = function; +} + +// Preinstantiate Objects ////////////////////////////////////////////////////// + +TwoWire Wire = TwoWire(); + diff --git a/libraries/Wire/Wire.h b/libraries/Wire/Wire.h new file mode 100644 index 000000000..c9103510d --- /dev/null +++ b/libraries/Wire/Wire.h @@ -0,0 +1,86 @@ +/* + TwoWire.h - TWI/I2C library for Arduino & Wiring + Copyright (c) 2006 Nicholas Zambetti. All right reserved. + + This library is free software; you can redistribute it and/or + modify it under the terms of the GNU Lesser General Public + License as published by the Free Software Foundation; either + version 2.1 of the License, or (at your option) any later version. + + This library 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 + Lesser General Public License for more details. + + You should have received a copy of the GNU Lesser General Public + License along with this library; if not, write to the Free Software + Foundation, Inc., 51 Franklin St, Fifth Floor, Boston, MA 02110-1301 USA + + Modified 2012 by Todd Krein (todd@krein.org) to implement repeated starts +*/ + +#ifndef TwoWire_h +#define TwoWire_h + +#include +#include "Stream.h" + + + +#define BUFFER_LENGTH 32 + +class TwoWire : public Stream +{ + private: + static uint8_t rxBuffer[]; + static uint8_t rxBufferIndex; + static uint8_t rxBufferLength; + + static uint8_t txAddress; + static uint8_t txBuffer[]; + static uint8_t txBufferIndex; + static uint8_t txBufferLength; + + static uint8_t transmitting; + static void (*user_onRequest)(void); + static void (*user_onReceive)(int); + static void onRequestService(void); + static void onReceiveService(uint8_t*, int); + public: + TwoWire(); + void pins(int sda, int scl); + void begin(); + void begin(uint8_t); + void begin(int); + void setClock(uint32_t); + void beginTransmission(uint8_t); + void beginTransmission(int); + uint8_t endTransmission(void); + uint8_t endTransmission(uint8_t); + size_t requestFrom(uint8_t address, size_t size, bool sendStop); + + uint8_t requestFrom(uint8_t, uint8_t); + uint8_t requestFrom(uint8_t, uint8_t, uint8_t); + uint8_t requestFrom(int, int); + uint8_t requestFrom(int, int, int); + + virtual size_t write(uint8_t); + virtual size_t write(const uint8_t *, size_t); + virtual int available(void); + virtual int read(void); + virtual int peek(void); + virtual void flush(void); + void onReceive( void (*)(int) ); + void onRequest( void (*)(void) ); + + inline size_t write(unsigned long n) { return write((uint8_t)n); } + inline size_t write(long n) { return write((uint8_t)n); } + inline size_t write(unsigned int n) { return write((uint8_t)n); } + inline size_t write(int n) { return write((uint8_t)n); } + using Print::write; +}; + +extern TwoWire Wire; + +#endif + diff --git a/libraries/Wire/keywords.txt b/libraries/Wire/keywords.txt new file mode 100644 index 000000000..ff3147592 --- /dev/null +++ b/libraries/Wire/keywords.txt @@ -0,0 +1,32 @@ +####################################### +# Syntax Coloring Map For Wire +####################################### + +####################################### +# Datatypes (KEYWORD1) +####################################### + +####################################### +# Methods and Functions (KEYWORD2) +####################################### + +begin KEYWORD2 +setClock KEYWORD2 +beginTransmission KEYWORD2 +endTransmission KEYWORD2 +requestFrom KEYWORD2 +send KEYWORD2 +receive KEYWORD2 +onReceive KEYWORD2 +onRequest KEYWORD2 + +####################################### +# Instances (KEYWORD2) +####################################### + +Wire KEYWORD2 + +####################################### +# Constants (LITERAL1) +####################################### + diff --git a/libraries/Wire/library.properties b/libraries/Wire/library.properties new file mode 100644 index 000000000..718bce406 --- /dev/null +++ b/libraries/Wire/library.properties @@ -0,0 +1,8 @@ +name=Wire +version=1.0 +author=Arduino +maintainer=Arduino +sentence=Allows the communication between devices or sensors connected via Two Wire Interface Bus. For all Arduino boards, BUT Arduino DUE. +paragraph= +url=http://arduino.cc/en/Reference/Wire +architectures=esp8266 diff --git a/libraries/Wire/utility/i2c.c b/libraries/Wire/utility/i2c.c new file mode 100644 index 000000000..cc7fdcf2a --- /dev/null +++ b/libraries/Wire/utility/i2c.c @@ -0,0 +1,175 @@ +#include +#include "i2c.h" + + +#include "ets_sys.h" +#include "osapi.h" +#include "gpio.h" + +size_t ets_printf(const char*, ...); +#define DEBUGV ets_printf + +static uint8_t s_sda_pin = 0; +static uint8_t s_scl_pin = 2; + + +static inline void i2c_set(int sda, int scl) +{ + digitalWrite(s_sda_pin, sda); + digitalWrite(s_scl_pin, scl); +} + +static inline void i2c_set_sda(int sda) +{ + digitalWrite(s_sda_pin, sda); +} + +static inline void i2c_set_scl(int scl) +{ + digitalWrite(s_scl_pin, scl); +} + +static inline uint8_t i2c_get_sda() +{ + return GPIO_INPUT_GET(GPIO_ID_PIN(s_sda_pin)); +} + +static inline void i2c_wait() +{ + delayMicroseconds(5); +} + +void i2c_init(int sda_pin, int scl_pin) +{ + s_sda_pin = sda_pin; + s_scl_pin = scl_pin; + pinMode(sda_pin, OUTPUT_OPEN_DRAIN); + pinMode(scl_pin, OUTPUT_OPEN_DRAIN); + i2c_set(1, 1); + i2c_wait(); +} + + +void i2c_release() +{ + pinMode(s_sda_pin, INPUT); + pinMode(s_scl_pin, INPUT); +} + +void i2c_start() +{ + i2c_set(1, 1); + i2c_wait(); + i2c_set_sda(0); + i2c_wait(); + i2c_wait(); + i2c_set_scl(0); + i2c_wait(); +} + +void i2c_stop() +{ + i2c_wait(); + i2c_set_scl(1); + i2c_wait(); + i2c_set_sda(1); + i2c_wait(); +} + +void i2c_set_ack(int ack) +{ + i2c_set_sda(!ack); + i2c_wait(); + i2c_set_scl(1); + i2c_wait(); + i2c_set_scl(0); + i2c_wait(); + i2c_set_sda(0); + i2c_wait(); +} + +int i2c_get_ack() +{ + i2c_wait(); + i2c_set_scl(1); + i2c_wait(); + int result = i2c_get_sda(); + i2c_set_scl(0); + i2c_wait(); + i2c_set_sda(0); + i2c_wait(); + return result; +} + +uint8_t i2c_read(void) +{ + uint8_t result = 0; + for (int i = 7; i >= 0; --i) + { + i2c_wait(); + i2c_set_scl(1); + i2c_wait(); + result <<= 1; + result |= i2c_get_sda(); + i2c_wait(); // <- remove + i2c_set_scl(0); + i2c_wait(); + } +} + + +void i2c_write(uint8_t val) +{ + for (int i = 7; i >= 0; --i) + { + i2c_set_sda((val >> i) & 1); + i2c_wait(); + i2c_set_scl(1); + i2c_wait(); + i2c_set_scl(0); + i2c_wait(); + } + i2c_set_sda(1); +} + +size_t i2c_master_read_from(int address, uint8_t* data, size_t size, bool sendStop) +{ + + DEBUGV("\r\nrf: %02x %08x %d\r\n", address, data, size); + i2c_start(); + i2c_write(address << 1 | 1); + int ack = i2c_get_ack(); + uint8_t* end = data + size; + for (;data != end; ++data ) + { + *data = i2c_read(); + DEBUGV("r%d ", *data); + if (data == end - 1) + i2c_set_ack(1); + else + i2c_set_ack(0); + } + DEBUGV("s\r\n", *data); + if (sendStop) + i2c_stop(); + return size; +} + +size_t i2c_master_write_to(int address, const uint8_t* data, size_t size, bool sendStop) +{ + i2c_start(); + i2c_write(address << 1); + int ack = i2c_get_ack(); + const uint8_t* end = data + size; + for (;data != end; ++data ) + { + i2c_write(*data); + ack = i2c_get_ack(); + } + if (sendStop) + i2c_stop(); + return size; +} + + + diff --git a/libraries/Wire/utility/i2c.cpp b/libraries/Wire/utility/i2c.cpp new file mode 100644 index 000000000..e2ce0bb18 --- /dev/null +++ b/libraries/Wire/utility/i2c.cpp @@ -0,0 +1,214 @@ +#include +#include "i2c.h" + +extern "C" { +#include "ets_sys.h" +#include "osapi.h" +#include "gpio.h" + +size_t ets_printf(const char*, ...); +#define DEBUGV ets_printf +} + +static uint8_t s_sda_pin = 0; +static uint8_t s_scl_pin = 2; +static uint32_t s_i2c_delay = 5; + +static inline void i2c_set(int sda, int scl) +{ + digitalWrite(s_sda_pin, sda); + digitalWrite(s_scl_pin, scl); +} + +static inline void i2c_set_sda(int sda) +{ + digitalWrite(s_sda_pin, sda); +} + +static inline void i2c_set_scl(int scl) +{ + digitalWrite(s_scl_pin, scl); +} + +static inline uint8_t i2c_get_sda() +{ + return GPIO_INPUT_GET(GPIO_ID_PIN(s_sda_pin)); +} + +static inline void i2c_wait() +{ + delayMicroseconds(5); +} + +void i2c_freq(int freq_hz) +{ + s_i2c_delay = 1000000 / freq_hz / 4 - 1; + if (s_i2c_delay < 0) + s_i2c_delay = 0; +} + +void i2c_init(int sda_pin, int scl_pin) +{ + s_sda_pin = sda_pin; + s_scl_pin = scl_pin; + pinMode(sda_pin, OUTPUT_OPEN_DRAIN); + pinMode(scl_pin, OUTPUT_OPEN_DRAIN); + i2c_set(1, 1); + i2c_wait(); +} + + +void i2c_release() +{ + pinMode(s_sda_pin, INPUT); + pinMode(s_scl_pin, INPUT); +} + +void i2c_start() +{ + i2c_set(1, 1); + i2c_wait(); + i2c_set_sda(0); + i2c_wait(); + i2c_wait(); + i2c_set_scl(0); + i2c_wait(); +} + +void i2c_stop() +{ + i2c_wait(); + i2c_set_scl(1); + i2c_wait(); + i2c_set_sda(1); + i2c_wait(); +} + +void i2c_set_ack(int ack) +{ + i2c_set_sda(!ack); + i2c_wait(); + i2c_set_scl(1); + i2c_wait(); + i2c_set_scl(0); + i2c_wait(); + i2c_set_sda(0); + i2c_wait(); +} + +int i2c_get_ack() +{ + i2c_wait(); + i2c_set_scl(1); + i2c_wait(); + int result = i2c_get_sda(); + i2c_set_scl(0); + i2c_wait(); + i2c_set_sda(0); + i2c_wait(); + return result; +} + +uint8_t i2c_read(void) +{ + uint8_t result = 0; + for (int i = 7; i >= 0; --i) + { + i2c_wait(); + i2c_set_scl(1); + i2c_wait(); + result <<= 1; + result |= i2c_get_sda(); + i2c_wait(); // <- remove + i2c_set_scl(0); + i2c_wait(); + } +} + + +void i2c_write(uint8_t val) +{ + for (int i = 7; i >= 0; --i) + { + i2c_set_sda((val >> i) & 1); + i2c_wait(); + i2c_set_scl(1); + i2c_wait(); + i2c_set_scl(0); + i2c_wait(); + } + i2c_set_sda(1); +} + +size_t i2c_master_read_from(int address, uint8_t* data, size_t size, bool sendStop) +{ + i2c_start(); + i2c_write(address << 1 | 1); + int ack = i2c_get_ack(); + uint8_t* end = data + size; + for (;data != end; ++data ) + { + *data = i2c_read(); + if (data == end - 1) + i2c_set_ack(1); + else + i2c_set_ack(0); + } + if (sendStop) + i2c_stop(); + return size; +} + +size_t i2c_master_write_to(int address, const uint8_t* data, size_t size, bool sendStop) +{ + i2c_start(); + i2c_write(address << 1); + int ack = i2c_get_ack(); + const uint8_t* end = data + size; + for (;data != end; ++data ) + { + i2c_write(*data); + ack = i2c_get_ack(); + } + if (sendStop) + i2c_stop(); + return size; +} + +// some stubs for libraries that use private twi.h interface +extern "C" +{ + void twi_init(void) { } + + void twi_setAddress(uint8_t) { } + + uint8_t twi_readFrom(uint8_t addr, uint8_t* data, uint8_t size, uint8_t sendStop) + { + return i2c_master_read_from(addr, data, size, sendStop); + } + + uint8_t twi_writeTo(uint8_t addr, uint8_t* data, uint8_t size, uint8_t wait, uint8_t sendStop) + { + return i2c_master_write_to(addr, data, size, sendStop); + } + + uint8_t twi_transmit(const uint8_t* data, uint8_t length) + { + + } + + + void twi_attachSlaveRxEvent( void (*)(uint8_t*, int) ) { } + void twi_attachSlaveTxEvent( void (*)(void) ) { } + void twi_reply(uint8_t) { } + void twi_stop(void) + { + i2c_stop(); + } + + void twi_releaseBus(void) + { + i2c_set(1, 1); + } +} + diff --git a/libraries/Wire/utility/i2c.h b/libraries/Wire/utility/i2c.h new file mode 100644 index 000000000..193e64f41 --- /dev/null +++ b/libraries/Wire/utility/i2c.h @@ -0,0 +1,27 @@ +#ifndef I2C_H +#define I2C_H + +#include + +void i2c_init(int sda_pin, int scl_pin); +void i2c_freq(int freq_hz); +void i2c_release(); +void i2c_start(); +void i2c_stop(); +void i2c_set_ack(int ack); +int i2c_get_ack(); +uint8_t i2c_read(void); +void i2c_write(uint8_t val); + + +size_t i2c_master_read_from(int address, uint8_t* data, size_t size, bool sendStop); +size_t i2c_master_write_to(int address, const uint8_t* data, size_t size, bool sendStop); + +// todo: implement i2c slave functions +// +// void i2c_slave_setAddress(uint8_t); +// int i2c_slave_transmit(const uint8_t* data, size_t size); +// void i2c_slave_attach_rx_callback( void (*)(uint8_t*, int) ); +// void i2c_slave_attach_tx_callback( void (*)(void) ); + +#endif//I2C_H diff --git a/libraries/Wire/utility/twi.c.unused b/libraries/Wire/utility/twi.c.unused new file mode 100644 index 000000000..201d7d1bb --- /dev/null +++ b/libraries/Wire/utility/twi.c.unused @@ -0,0 +1,527 @@ +/* + twi.c - TWI/I2C library for Wiring & Arduino + Copyright (c) 2006 Nicholas Zambetti. All right reserved. + + This library is free software; you can redistribute it and/or + modify it under the terms of the GNU Lesser General Public + License as published by the Free Software Foundation; either + version 2.1 of the License, or (at your option) any later version. + + This library 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 + Lesser General Public License for more details. + + You should have received a copy of the GNU Lesser General Public + License along with this library; if not, write to the Free Software + Foundation, Inc., 51 Franklin St, Fifth Floor, Boston, MA 02110-1301 USA + + Modified 2012 by Todd Krein (todd@krein.org) to implement repeated starts +*/ + +#include +#include +#include +#include +#include +#include +#include "Arduino.h" // for digitalWrite + +#ifndef cbi +#define cbi(sfr, bit) (_SFR_BYTE(sfr) &= ~_BV(bit)) +#endif + +#ifndef sbi +#define sbi(sfr, bit) (_SFR_BYTE(sfr) |= _BV(bit)) +#endif + +#include "pins_arduino.h" +#include "twi.h" + +static volatile uint8_t twi_state; +static volatile uint8_t twi_slarw; +static volatile uint8_t twi_sendStop; // should the transaction end with a stop +static volatile uint8_t twi_inRepStart; // in the middle of a repeated start + +static void (*twi_onSlaveTransmit)(void); +static void (*twi_onSlaveReceive)(uint8_t*, int); + +static uint8_t twi_masterBuffer[TWI_BUFFER_LENGTH]; +static volatile uint8_t twi_masterBufferIndex; +static volatile uint8_t twi_masterBufferLength; + +static uint8_t twi_txBuffer[TWI_BUFFER_LENGTH]; +static volatile uint8_t twi_txBufferIndex; +static volatile uint8_t twi_txBufferLength; + +static uint8_t twi_rxBuffer[TWI_BUFFER_LENGTH]; +static volatile uint8_t twi_rxBufferIndex; + +static volatile uint8_t twi_error; + +/* + * Function twi_init + * Desc readys twi pins and sets twi bitrate + * Input none + * Output none + */ +void twi_init(void) +{ + // initialize state + twi_state = TWI_READY; + twi_sendStop = true; // default value + twi_inRepStart = false; + + // activate internal pullups for twi. + digitalWrite(SDA, 1); + digitalWrite(SCL, 1); + + // initialize twi prescaler and bit rate + cbi(TWSR, TWPS0); + cbi(TWSR, TWPS1); + TWBR = ((F_CPU / TWI_FREQ) - 16) / 2; + + /* twi bit rate formula from atmega128 manual pg 204 + SCL Frequency = CPU Clock Frequency / (16 + (2 * TWBR)) + note: TWBR should be 10 or higher for master mode + It is 72 for a 16mhz Wiring board with 100kHz TWI */ + + // enable twi module, acks, and twi interrupt + TWCR = _BV(TWEN) | _BV(TWIE) | _BV(TWEA); +} + +/* + * Function twi_slaveInit + * Desc sets slave address and enables interrupt + * Input none + * Output none + */ +void twi_setAddress(uint8_t address) +{ + // set twi slave address (skip over TWGCE bit) + TWAR = address << 1; +} + +/* + * Function twi_readFrom + * Desc attempts to become twi bus master and read a + * series of bytes from a device on the bus + * Input address: 7bit i2c device address + * data: pointer to byte array + * length: number of bytes to read into array + * sendStop: Boolean indicating whether to send a stop at the end + * Output number of bytes read + */ +uint8_t twi_readFrom(uint8_t address, uint8_t* data, uint8_t length, uint8_t sendStop) +{ + uint8_t i; + + // ensure data will fit into buffer + if(TWI_BUFFER_LENGTH < length){ + return 0; + } + + // wait until twi is ready, become master receiver + while(TWI_READY != twi_state){ + continue; + } + twi_state = TWI_MRX; + twi_sendStop = sendStop; + // reset error state (0xFF.. no error occured) + twi_error = 0xFF; + + // initialize buffer iteration vars + twi_masterBufferIndex = 0; + twi_masterBufferLength = length-1; // This is not intuitive, read on... + // On receive, the previously configured ACK/NACK setting is transmitted in + // response to the received byte before the interrupt is signalled. + // Therefor we must actually set NACK when the _next_ to last byte is + // received, causing that NACK to be sent in response to receiving the last + // expected byte of data. + + // build sla+w, slave device address + w bit + twi_slarw = TW_READ; + twi_slarw |= address << 1; + + if (true == twi_inRepStart) { + // if we're in the repeated start state, then we've already sent the start, + // (@@@ we hope), and the TWI statemachine is just waiting for the address byte. + // We need to remove ourselves from the repeated start state before we enable interrupts, + // since the ISR is ASYNC, and we could get confused if we hit the ISR before cleaning + // up. Also, don't enable the START interrupt. There may be one pending from the + // repeated start that we sent outselves, and that would really confuse things. + twi_inRepStart = false; // remember, we're dealing with an ASYNC ISR + TWDR = twi_slarw; + TWCR = _BV(TWINT) | _BV(TWEA) | _BV(TWEN) | _BV(TWIE); // enable INTs, but not START + } + else + // send start condition + TWCR = _BV(TWEN) | _BV(TWIE) | _BV(TWEA) | _BV(TWINT) | _BV(TWSTA); + + // wait for read operation to complete + while(TWI_MRX == twi_state){ + continue; + } + + if (twi_masterBufferIndex < length) + length = twi_masterBufferIndex; + + // copy twi buffer to data + for(i = 0; i < length; ++i){ + data[i] = twi_masterBuffer[i]; + } + + return length; +} + +/* + * Function twi_writeTo + * Desc attempts to become twi bus master and write a + * series of bytes to a device on the bus + * Input address: 7bit i2c device address + * data: pointer to byte array + * length: number of bytes in array + * wait: boolean indicating to wait for write or not + * sendStop: boolean indicating whether or not to send a stop at the end + * Output 0 .. success + * 1 .. length to long for buffer + * 2 .. address send, NACK received + * 3 .. data send, NACK received + * 4 .. other twi error (lost bus arbitration, bus error, ..) + */ +uint8_t twi_writeTo(uint8_t address, uint8_t* data, uint8_t length, uint8_t wait, uint8_t sendStop) +{ + uint8_t i; + + // ensure data will fit into buffer + if(TWI_BUFFER_LENGTH < length){ + return 1; + } + + // wait until twi is ready, become master transmitter + while(TWI_READY != twi_state){ + continue; + } + twi_state = TWI_MTX; + twi_sendStop = sendStop; + // reset error state (0xFF.. no error occured) + twi_error = 0xFF; + + // initialize buffer iteration vars + twi_masterBufferIndex = 0; + twi_masterBufferLength = length; + + // copy data to twi buffer + for(i = 0; i < length; ++i){ + twi_masterBuffer[i] = data[i]; + } + + // build sla+w, slave device address + w bit + twi_slarw = TW_WRITE; + twi_slarw |= address << 1; + + // if we're in a repeated start, then we've already sent the START + // in the ISR. Don't do it again. + // + if (true == twi_inRepStart) { + // if we're in the repeated start state, then we've already sent the start, + // (@@@ we hope), and the TWI statemachine is just waiting for the address byte. + // We need to remove ourselves from the repeated start state before we enable interrupts, + // since the ISR is ASYNC, and we could get confused if we hit the ISR before cleaning + // up. Also, don't enable the START interrupt. There may be one pending from the + // repeated start that we sent outselves, and that would really confuse things. + twi_inRepStart = false; // remember, we're dealing with an ASYNC ISR + TWDR = twi_slarw; + TWCR = _BV(TWINT) | _BV(TWEA) | _BV(TWEN) | _BV(TWIE); // enable INTs, but not START + } + else + // send start condition + TWCR = _BV(TWINT) | _BV(TWEA) | _BV(TWEN) | _BV(TWIE) | _BV(TWSTA); // enable INTs + + // wait for write operation to complete + while(wait && (TWI_MTX == twi_state)){ + continue; + } + + if (twi_error == 0xFF) + return 0; // success + else if (twi_error == TW_MT_SLA_NACK) + return 2; // error: address send, nack received + else if (twi_error == TW_MT_DATA_NACK) + return 3; // error: data send, nack received + else + return 4; // other twi error +} + +/* + * Function twi_transmit + * Desc fills slave tx buffer with data + * must be called in slave tx event callback + * Input data: pointer to byte array + * length: number of bytes in array + * Output 1 length too long for buffer + * 2 not slave transmitter + * 0 ok + */ +uint8_t twi_transmit(const uint8_t* data, uint8_t length) +{ + uint8_t i; + + // ensure data will fit into buffer + if(TWI_BUFFER_LENGTH < length){ + return 1; + } + + // ensure we are currently a slave transmitter + if(TWI_STX != twi_state){ + return 2; + } + + // set length and copy data into tx buffer + twi_txBufferLength = length; + for(i = 0; i < length; ++i){ + twi_txBuffer[i] = data[i]; + } + + return 0; +} + +/* + * Function twi_attachSlaveRxEvent + * Desc sets function called before a slave read operation + * Input function: callback function to use + * Output none + */ +void twi_attachSlaveRxEvent( void (*function)(uint8_t*, int) ) +{ + twi_onSlaveReceive = function; +} + +/* + * Function twi_attachSlaveTxEvent + * Desc sets function called before a slave write operation + * Input function: callback function to use + * Output none + */ +void twi_attachSlaveTxEvent( void (*function)(void) ) +{ + twi_onSlaveTransmit = function; +} + +/* + * Function twi_reply + * Desc sends byte or readys receive line + * Input ack: byte indicating to ack or to nack + * Output none + */ +void twi_reply(uint8_t ack) +{ + // transmit master read ready signal, with or without ack + if(ack){ + TWCR = _BV(TWEN) | _BV(TWIE) | _BV(TWINT) | _BV(TWEA); + }else{ + TWCR = _BV(TWEN) | _BV(TWIE) | _BV(TWINT); + } +} + +/* + * Function twi_stop + * Desc relinquishes bus master status + * Input none + * Output none + */ +void twi_stop(void) +{ + // send stop condition + TWCR = _BV(TWEN) | _BV(TWIE) | _BV(TWEA) | _BV(TWINT) | _BV(TWSTO); + + // wait for stop condition to be exectued on bus + // TWINT is not set after a stop condition! + while(TWCR & _BV(TWSTO)){ + continue; + } + + // update twi state + twi_state = TWI_READY; +} + +/* + * Function twi_releaseBus + * Desc releases bus control + * Input none + * Output none + */ +void twi_releaseBus(void) +{ + // release bus + TWCR = _BV(TWEN) | _BV(TWIE) | _BV(TWEA) | _BV(TWINT); + + // update twi state + twi_state = TWI_READY; +} + +ISR(TWI_vect) +{ + switch(TW_STATUS){ + // All Master + case TW_START: // sent start condition + case TW_REP_START: // sent repeated start condition + // copy device address and r/w bit to output register and ack + TWDR = twi_slarw; + twi_reply(1); + break; + + // Master Transmitter + case TW_MT_SLA_ACK: // slave receiver acked address + case TW_MT_DATA_ACK: // slave receiver acked data + // if there is data to send, send it, otherwise stop + if(twi_masterBufferIndex < twi_masterBufferLength){ + // copy data to output register and ack + TWDR = twi_masterBuffer[twi_masterBufferIndex++]; + twi_reply(1); + }else{ + if (twi_sendStop) + twi_stop(); + else { + twi_inRepStart = true; // we're gonna send the START + // don't enable the interrupt. We'll generate the start, but we + // avoid handling the interrupt until we're in the next transaction, + // at the point where we would normally issue the start. + TWCR = _BV(TWINT) | _BV(TWSTA)| _BV(TWEN) ; + twi_state = TWI_READY; + } + } + break; + case TW_MT_SLA_NACK: // address sent, nack received + twi_error = TW_MT_SLA_NACK; + twi_stop(); + break; + case TW_MT_DATA_NACK: // data sent, nack received + twi_error = TW_MT_DATA_NACK; + twi_stop(); + break; + case TW_MT_ARB_LOST: // lost bus arbitration + twi_error = TW_MT_ARB_LOST; + twi_releaseBus(); + break; + + // Master Receiver + case TW_MR_DATA_ACK: // data received, ack sent + // put byte into buffer + twi_masterBuffer[twi_masterBufferIndex++] = TWDR; + case TW_MR_SLA_ACK: // address sent, ack received + // ack if more bytes are expected, otherwise nack + if(twi_masterBufferIndex < twi_masterBufferLength){ + twi_reply(1); + }else{ + twi_reply(0); + } + break; + case TW_MR_DATA_NACK: // data received, nack sent + // put final byte into buffer + twi_masterBuffer[twi_masterBufferIndex++] = TWDR; + if (twi_sendStop) + twi_stop(); + else { + twi_inRepStart = true; // we're gonna send the START + // don't enable the interrupt. We'll generate the start, but we + // avoid handling the interrupt until we're in the next transaction, + // at the point where we would normally issue the start. + TWCR = _BV(TWINT) | _BV(TWSTA)| _BV(TWEN) ; + twi_state = TWI_READY; + } + break; + case TW_MR_SLA_NACK: // address sent, nack received + twi_stop(); + break; + // TW_MR_ARB_LOST handled by TW_MT_ARB_LOST case + + // Slave Receiver + case TW_SR_SLA_ACK: // addressed, returned ack + case TW_SR_GCALL_ACK: // addressed generally, returned ack + case TW_SR_ARB_LOST_SLA_ACK: // lost arbitration, returned ack + case TW_SR_ARB_LOST_GCALL_ACK: // lost arbitration, returned ack + // enter slave receiver mode + twi_state = TWI_SRX; + // indicate that rx buffer can be overwritten and ack + twi_rxBufferIndex = 0; + twi_reply(1); + break; + case TW_SR_DATA_ACK: // data received, returned ack + case TW_SR_GCALL_DATA_ACK: // data received generally, returned ack + // if there is still room in the rx buffer + if(twi_rxBufferIndex < TWI_BUFFER_LENGTH){ + // put byte in buffer and ack + twi_rxBuffer[twi_rxBufferIndex++] = TWDR; + twi_reply(1); + }else{ + // otherwise nack + twi_reply(0); + } + break; + case TW_SR_STOP: // stop or repeated start condition received + // put a null char after data if there's room + if(twi_rxBufferIndex < TWI_BUFFER_LENGTH){ + twi_rxBuffer[twi_rxBufferIndex] = '\0'; + } + // sends ack and stops interface for clock stretching + twi_stop(); + // callback to user defined callback + twi_onSlaveReceive(twi_rxBuffer, twi_rxBufferIndex); + // since we submit rx buffer to "wire" library, we can reset it + twi_rxBufferIndex = 0; + // ack future responses and leave slave receiver state + twi_releaseBus(); + break; + case TW_SR_DATA_NACK: // data received, returned nack + case TW_SR_GCALL_DATA_NACK: // data received generally, returned nack + // nack back at master + twi_reply(0); + break; + + // Slave Transmitter + case TW_ST_SLA_ACK: // addressed, returned ack + case TW_ST_ARB_LOST_SLA_ACK: // arbitration lost, returned ack + // enter slave transmitter mode + twi_state = TWI_STX; + // ready the tx buffer index for iteration + twi_txBufferIndex = 0; + // set tx buffer length to be zero, to verify if user changes it + twi_txBufferLength = 0; + // request for txBuffer to be filled and length to be set + // note: user must call twi_transmit(bytes, length) to do this + twi_onSlaveTransmit(); + // if they didn't change buffer & length, initialize it + if(0 == twi_txBufferLength){ + twi_txBufferLength = 1; + twi_txBuffer[0] = 0x00; + } + // transmit first byte from buffer, fall + case TW_ST_DATA_ACK: // byte sent, ack returned + // copy data to output register + TWDR = twi_txBuffer[twi_txBufferIndex++]; + // if there is more to send, ack, otherwise nack + if(twi_txBufferIndex < twi_txBufferLength){ + twi_reply(1); + }else{ + twi_reply(0); + } + break; + case TW_ST_DATA_NACK: // received nack, we are done + case TW_ST_LAST_DATA: // received ack, but we are done already! + // ack future responses + twi_reply(1); + // leave slave receiver state + twi_state = TWI_READY; + break; + + // All + case TW_NO_INFO: // no state information + break; + case TW_BUS_ERROR: // bus error, illegal stop/start + twi_error = TW_BUS_ERROR; + twi_stop(); + break; + } +} + diff --git a/libraries/Wire/utility/twi.h b/libraries/Wire/utility/twi.h new file mode 100644 index 000000000..652659339 --- /dev/null +++ b/libraries/Wire/utility/twi.h @@ -0,0 +1,53 @@ +/* + twi.h - TWI/I2C library for Wiring & Arduino + Copyright (c) 2006 Nicholas Zambetti. All right reserved. + + This library is free software; you can redistribute it and/or + modify it under the terms of the GNU Lesser General Public + License as published by the Free Software Foundation; either + version 2.1 of the License, or (at your option) any later version. + + This library 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 + Lesser General Public License for more details. + + You should have received a copy of the GNU Lesser General Public + License along with this library; if not, write to the Free Software + Foundation, Inc., 51 Franklin St, Fifth Floor, Boston, MA 02110-1301 USA +*/ + +#ifndef twi_h +#define twi_h + + #include + + //#define ATMEGA8 + + #ifndef TWI_FREQ + #define TWI_FREQ 100000L + #endif + + #ifndef TWI_BUFFER_LENGTH + #define TWI_BUFFER_LENGTH 32 + #endif + + #define TWI_READY 0 + #define TWI_MRX 1 + #define TWI_MTX 2 + #define TWI_SRX 3 + #define TWI_STX 4 + + void twi_init(void); + void twi_setAddress(uint8_t); + uint8_t twi_readFrom(uint8_t, uint8_t*, uint8_t, uint8_t); + uint8_t twi_writeTo(uint8_t, uint8_t*, uint8_t, uint8_t, uint8_t); + uint8_t twi_transmit(const uint8_t*, uint8_t); + void twi_attachSlaveRxEvent( void (*)(uint8_t*, int) ); + void twi_attachSlaveTxEvent( void (*)(void) ); + void twi_reply(uint8_t); + void twi_stop(void); + void twi_releaseBus(void); + +#endif +