diff options
Diffstat (limited to 'libraries/Wire')
| -rw-r--r-- | libraries/Wire/Wire.cpp | 303 | ||||
| -rw-r--r-- | libraries/Wire/Wire.h | 80 | ||||
| -rw-r--r-- | libraries/Wire/examples/SFRRanger_reader/SFRRanger_reader.ino | 87 | ||||
| -rw-r--r-- | libraries/Wire/examples/digital_potentiometer/digital_potentiometer.ino | 39 | ||||
| -rw-r--r-- | libraries/Wire/examples/master_reader/master_reader.ino | 32 | ||||
| -rw-r--r-- | libraries/Wire/examples/master_writer/master_writer.ino | 31 | ||||
| -rw-r--r-- | libraries/Wire/examples/slave_receiver/slave_receiver.ino | 38 | ||||
| -rw-r--r-- | libraries/Wire/examples/slave_sender/slave_sender.ino | 32 | ||||
| -rw-r--r-- | libraries/Wire/keywords.txt | 32 | ||||
| -rw-r--r-- | libraries/Wire/library.properties | 8 | ||||
| -rw-r--r-- | libraries/Wire/utility/twi.c | 527 | ||||
| -rw-r--r-- | libraries/Wire/utility/twi.h | 53 |
12 files changed, 1262 insertions, 0 deletions
diff --git a/libraries/Wire/Wire.cpp b/libraries/Wire/Wire.cpp new file mode 100644 index 0000000..553add7 --- /dev/null +++ b/libraries/Wire/Wire.cpp @@ -0,0 +1,303 @@ +/* + 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 <stdlib.h> + #include <string.h> + #include <inttypes.h> + #include "twi.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::begin(void) +{ + rxBufferIndex = 0; + rxBufferLength = 0; + + txBufferIndex = 0; + txBufferLength = 0; + + twi_init(); +} + +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) +{ + TWBR = ((F_CPU / frequency) - 16) / 2; +} + +uint8_t TwoWire::requestFrom(uint8_t address, uint8_t quantity, uint8_t sendStop) +{ + // clamp to buffer length + if(quantity > BUFFER_LENGTH){ + quantity = BUFFER_LENGTH; + } + // perform blocking read into buffer + uint8_t read = twi_readFrom(address, rxBuffer, quantity, sendStop); + // set rx buffer iterator vars + rxBufferIndex = 0; + rxBufferLength = read; + + return read; +} + +uint8_t TwoWire::requestFrom(uint8_t address, uint8_t quantity) +{ + return requestFrom((uint8_t)address, (uint8_t)quantity, (uint8_t)true); +} + +uint8_t TwoWire::requestFrom(int address, int quantity) +{ + return requestFrom((uint8_t)address, (uint8_t)quantity, (uint8_t)true); +} + +uint8_t TwoWire::requestFrom(int address, int quantity, int sendStop) +{ + return requestFrom((uint8_t)address, (uint8_t)quantity, (uint8_t)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 = twi_writeTo(txAddress, txBuffer, txBufferLength, 1, 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 + twi_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 + twi_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 0000000..732bdc3 --- /dev/null +++ b/libraries/Wire/Wire.h @@ -0,0 +1,80 @@ +/* + 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 <inttypes.h> +#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 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); + 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/examples/SFRRanger_reader/SFRRanger_reader.ino b/libraries/Wire/examples/SFRRanger_reader/SFRRanger_reader.ino new file mode 100644 index 0000000..d97a9e3 --- /dev/null +++ b/libraries/Wire/examples/SFRRanger_reader/SFRRanger_reader.ino @@ -0,0 +1,87 @@ +// I2C SRF10 or SRF08 Devantech Ultrasonic Ranger Finder +// by Nicholas Zambetti <http://www.zambetti.com> +// and James Tichenor <http://www.jamestichenor.net> + +// Demonstrates use of the Wire library reading data from the +// Devantech Utrasonic Rangers SFR08 and SFR10 + +// Created 29 April 2006 + +// This example code is in the public domain. + + +#include <Wire.h> + +void setup() +{ + Wire.begin(); // join i2c bus (address optional for master) + Serial.begin(9600); // start serial communication at 9600bps +} + +int reading = 0; + +void loop() +{ + // step 1: instruct sensor to read echoes + Wire.beginTransmission(112); // transmit to device #112 (0x70) + // the address specified in the datasheet is 224 (0xE0) + // but i2c adressing uses the high 7 bits so it's 112 + Wire.write(byte(0x00)); // sets register pointer to the command register (0x00) + Wire.write(byte(0x50)); // command sensor to measure in "inches" (0x50) + // use 0x51 for centimeters + // use 0x52 for ping microseconds + Wire.endTransmission(); // stop transmitting + + // step 2: wait for readings to happen + delay(70); // datasheet suggests at least 65 milliseconds + + // step 3: instruct sensor to return a particular echo reading + Wire.beginTransmission(112); // transmit to device #112 + Wire.write(byte(0x02)); // sets register pointer to echo #1 register (0x02) + Wire.endTransmission(); // stop transmitting + + // step 4: request reading from sensor + Wire.requestFrom(112, 2); // request 2 bytes from slave device #112 + + // step 5: receive reading from sensor + if (2 <= Wire.available()) // if two bytes were received + { + reading = Wire.read(); // receive high byte (overwrites previous reading) + reading = reading << 8; // shift high byte to be high 8 bits + reading |= Wire.read(); // receive low byte as lower 8 bits + Serial.println(reading); // print the reading + } + + delay(250); // wait a bit since people have to read the output :) +} + + +/* + +// The following code changes the address of a Devantech Ultrasonic Range Finder (SRF10 or SRF08) +// usage: changeAddress(0x70, 0xE6); + +void changeAddress(byte oldAddress, byte newAddress) +{ + Wire.beginTransmission(oldAddress); + Wire.write(byte(0x00)); + Wire.write(byte(0xA0)); + Wire.endTransmission(); + + Wire.beginTransmission(oldAddress); + Wire.write(byte(0x00)); + Wire.write(byte(0xAA)); + Wire.endTransmission(); + + Wire.beginTransmission(oldAddress); + Wire.write(byte(0x00)); + Wire.write(byte(0xA5)); + Wire.endTransmission(); + + Wire.beginTransmission(oldAddress); + Wire.write(byte(0x00)); + Wire.write(newAddress); + Wire.endTransmission(); +} + +*/ diff --git a/libraries/Wire/examples/digital_potentiometer/digital_potentiometer.ino b/libraries/Wire/examples/digital_potentiometer/digital_potentiometer.ino new file mode 100644 index 0000000..4d1580a --- /dev/null +++ b/libraries/Wire/examples/digital_potentiometer/digital_potentiometer.ino @@ -0,0 +1,39 @@ +// I2C Digital Potentiometer +// by Nicholas Zambetti <http://www.zambetti.com> +// and Shawn Bonkowski <http://people.interaction-ivrea.it/s.bonkowski/> + +// Demonstrates use of the Wire library +// Controls AD5171 digital potentiometer via I2C/TWI + +// Created 31 March 2006 + +// This example code is in the public domain. + +// This example code is in the public domain. + + +#include <Wire.h> + +void setup() +{ + Wire.begin(); // join i2c bus (address optional for master) +} + +byte val = 0; + +void loop() +{ + Wire.beginTransmission(44); // transmit to device #44 (0x2c) + // device address is specified in datasheet + Wire.write(byte(0x00)); // sends instruction byte + Wire.write(val); // sends potentiometer value byte + Wire.endTransmission(); // stop transmitting + + val++; // increment value + if (val == 64) // if reached 64th position (max) + { + val = 0; // start over from lowest value + } + delay(500); +} + diff --git a/libraries/Wire/examples/master_reader/master_reader.ino b/libraries/Wire/examples/master_reader/master_reader.ino new file mode 100644 index 0000000..74f0155 --- /dev/null +++ b/libraries/Wire/examples/master_reader/master_reader.ino @@ -0,0 +1,32 @@ +// Wire Master Reader +// by Nicholas Zambetti <http://www.zambetti.com> + +// Demonstrates use of the Wire library +// Reads data from an I2C/TWI slave device +// Refer to the "Wire Slave Sender" example for use with this + +// Created 29 March 2006 + +// This example code is in the public domain. + + +#include <Wire.h> + +void setup() +{ + Wire.begin(); // join i2c bus (address optional for master) + Serial.begin(9600); // start serial for output +} + +void loop() +{ + Wire.requestFrom(2, 6); // request 6 bytes from slave device #2 + + while (Wire.available()) // slave may send less than requested + { + char c = Wire.read(); // receive a byte as character + Serial.print(c); // print the character + } + + delay(500); +} diff --git a/libraries/Wire/examples/master_writer/master_writer.ino b/libraries/Wire/examples/master_writer/master_writer.ino new file mode 100644 index 0000000..482e922 --- /dev/null +++ b/libraries/Wire/examples/master_writer/master_writer.ino @@ -0,0 +1,31 @@ +// Wire Master Writer +// by Nicholas Zambetti <http://www.zambetti.com> + +// Demonstrates use of the Wire library +// Writes data to an I2C/TWI slave device +// Refer to the "Wire Slave Receiver" example for use with this + +// Created 29 March 2006 + +// This example code is in the public domain. + + +#include <Wire.h> + +void setup() +{ + Wire.begin(); // join i2c bus (address optional for master) +} + +byte x = 0; + +void loop() +{ + Wire.beginTransmission(4); // transmit to device #4 + Wire.write("x is "); // sends five bytes + Wire.write(x); // sends one byte + Wire.endTransmission(); // stop transmitting + + x++; + delay(500); +} diff --git a/libraries/Wire/examples/slave_receiver/slave_receiver.ino b/libraries/Wire/examples/slave_receiver/slave_receiver.ino new file mode 100644 index 0000000..15eff9a --- /dev/null +++ b/libraries/Wire/examples/slave_receiver/slave_receiver.ino @@ -0,0 +1,38 @@ +// Wire Slave Receiver +// by Nicholas Zambetti <http://www.zambetti.com> + +// Demonstrates use of the Wire library +// Receives data as an I2C/TWI slave device +// Refer to the "Wire Master Writer" example for use with this + +// Created 29 March 2006 + +// This example code is in the public domain. + + +#include <Wire.h> + +void setup() +{ + Wire.begin(4); // join i2c bus with address #4 + Wire.onReceive(receiveEvent); // register event + Serial.begin(9600); // start serial for output +} + +void loop() +{ + delay(100); +} + +// function that executes whenever data is received from master +// this function is registered as an event, see setup() +void receiveEvent(int howMany) +{ + while (1 < Wire.available()) // loop through all but the last + { + char c = Wire.read(); // receive byte as a character + Serial.print(c); // print the character + } + int x = Wire.read(); // receive byte as an integer + Serial.println(x); // print the integer +} diff --git a/libraries/Wire/examples/slave_sender/slave_sender.ino b/libraries/Wire/examples/slave_sender/slave_sender.ino new file mode 100644 index 0000000..4437ab1 --- /dev/null +++ b/libraries/Wire/examples/slave_sender/slave_sender.ino @@ -0,0 +1,32 @@ +// Wire Slave Sender +// by Nicholas Zambetti <http://www.zambetti.com> + +// Demonstrates use of the Wire library +// Sends data as an I2C/TWI slave device +// Refer to the "Wire Master Reader" example for use with this + +// Created 29 March 2006 + +// This example code is in the public domain. + + +#include <Wire.h> + +void setup() +{ + Wire.begin(2); // join i2c bus with address #2 + Wire.onRequest(requestEvent); // register event +} + +void loop() +{ + delay(100); +} + +// function that executes whenever data is requested by master +// this function is registered as an event, see setup() +void requestEvent() +{ + Wire.write("hello "); // respond with message of 6 bytes + // as expected by master +} diff --git a/libraries/Wire/keywords.txt b/libraries/Wire/keywords.txt new file mode 100644 index 0000000..ff31475 --- /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 0000000..3246a75 --- /dev/null +++ b/libraries/Wire/library.properties @@ -0,0 +1,8 @@ +name=Wire +version=1.0 +author=Arduino +maintainer=Arduino <info@arduino.cc> +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=avr diff --git a/libraries/Wire/utility/twi.c b/libraries/Wire/utility/twi.c new file mode 100644 index 0000000..201d7d1 --- /dev/null +++ b/libraries/Wire/utility/twi.c @@ -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 <math.h> +#include <stdlib.h> +#include <inttypes.h> +#include <avr/io.h> +#include <avr/interrupt.h> +#include <compat/twi.h> +#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 0000000..6526593 --- /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 <inttypes.h> + + //#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 + |