From 8c2b5b979a75d109ae7cc306afc50d7ffe1e0366 Mon Sep 17 00:00:00 2001 From: Cristian Maglie Date: Wed, 4 Jan 2012 15:14:51 +0100 Subject: Moved libraries folder inside platform folder. Now libraries and examples are searched per board/platform --- libraries/Wire/Wire.cpp | 265 ++++++++++++++++++++++++++++++++++++++++++++++++ 1 file changed, 265 insertions(+) create mode 100755 libraries/Wire/Wire.cpp (limited to 'libraries/Wire/Wire.cpp') diff --git a/libraries/Wire/Wire.cpp b/libraries/Wire/Wire.cpp new file mode 100755 index 0000000..d83f478 --- /dev/null +++ b/libraries/Wire/Wire.cpp @@ -0,0 +1,265 @@ +/* + 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 +*/ + +extern "C" { + #include + #include + #include + #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); +} + +uint8_t TwoWire::requestFrom(uint8_t address, uint8_t quantity) +{ + // clamp to buffer length + if(quantity > BUFFER_LENGTH){ + quantity = BUFFER_LENGTH; + } + // perform blocking read into buffer + uint8_t read = twi_readFrom(address, rxBuffer, quantity); + // set rx buffer iterator vars + rxBufferIndex = 0; + rxBufferLength = read; + + return read; +} + +uint8_t TwoWire::requestFrom(int address, int quantity) +{ + return requestFrom((uint8_t)address, (uint8_t)quantity); +} + +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); +} + +uint8_t TwoWire::endTransmission(void) +{ + // transmit buffer (blocking) + int8_t ret = twi_writeTo(txAddress, txBuffer, txBufferLength, 1); + // reset tx buffer iterator vars + txBufferIndex = 0; + txBufferLength = 0; + // indicate that we are done transmitting + transmitting = 0; + return ret; +} + +// 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(); + -- cgit v1.2.3-18-g5258