taigrr/arduinolibs
1
0
Fork 0
mirror of https://github.com/taigrr/arduinolibs synced 2025-01-18 04:33:12 -08:00
Code Issues Projects Releases Wiki Activity

Refactor the I2C library API

Browse Source
This commit is contained in:
Rhys Weatherley 2012-05-18 09:37:42 +10:00
parent 5819690b42
commit 8a601d3a80
6 changed files with 277 additions and 157 deletions
Show Stats Download Patch File Download Diff File Expand all files Collapse all files

138
libraries/I2C/BitBangI2C.cpp
View File

@ -45,6 +45,9 @@ BitBangI2C::BitBangI2C(uint8_t dataPin, uint8_t clockPin)
: _dataPin(dataPin)
, _clockPin(clockPin)
, started(false)
, acked(true)
, inWrite(false)
, readCount(0)
{
// Initially set the CLOCK and DATA lines to be outputs in the high state.
pinMode(_clockPin, OUTPUT);
@ -53,26 +56,11 @@ BitBangI2C::BitBangI2C(uint8_t dataPin, uint8_t clockPin)
digitalWrite(_dataPin, HIGH);
}
/**
* \typedef BitBangI2C::ack_t
* \brief Type that represents an I2C ACK or NACK indication.
*/
unsigned int BitBangI2C::maxTransferSize() const
{
return 0xFFFF;
}
/**
* \var BitBangI2C::ACK
* \brief Indicates that an I2C operation was acknowledged.
*/
/**
* \var BitBangI2C::NACK
* \brief Indicates that an I2C operation was not acknowledged.
*/
/**
* \brief Transmits an I2C start condition on the bus.
*
* \sa startRead(), startWrite()
*/
void BitBangI2C::start()
{
pinMode(_dataPin, OUTPUT);
@ -87,11 +75,9 @@ void BitBangI2C::start()
digitalWrite(_clockPin, LOW);
i2cDelay();
started = true;
acked = true;
}
/**
* \brief Transmits an I2C stop condition on the bus.
*/
void BitBangI2C::stop()
{
pinMode(_dataPin, OUTPUT);
@ -101,6 +87,7 @@ void BitBangI2C::stop()
digitalWrite(_dataPin, HIGH);
i2cDelay();
started = false;
inWrite = false;
}
#define I2C_WRITE 0x00
@ -108,84 +95,77 @@ void BitBangI2C::stop()
#define I2C_READ 0x01
#define I2C_READ10 0xF1
/**
* \brief Starts a write operation by sending a start condition and the I2C control byte.
*
* The \a address must be the 7-bit or 10-bit address of the I2C slave
* on the bus.
*
* Returns BitBangI2C::ACK or BitBangI2C::NACK to indicate whether the
* read operation was acknowledged by the slave or not.
*
* \sa startWrite()
*/
BitBangI2C::ack_t BitBangI2C::startWrite(unsigned int address)
void BitBangI2C::startWrite(unsigned int address)
{
start();
inWrite = true;
if (address < 0x80) {
// 7-bit address.
return write((uint8_t)((address << 1) | I2C_WRITE));
write((uint8_t)((address << 1) | I2C_WRITE));
} else {
// 10-bit address.
if (write((uint8_t)(((address >> 7) & 0x06)) | I2C_WRITE10) == NACK)
return NACK;
return write((uint8_t)address);
write((uint8_t)(((address >> 7) & 0x06)) | I2C_WRITE10);
write((uint8_t)address);
}
}
/**
* \brief Starts a read operation by sending the start condition and the I2C control byte.
*
* The \a address must be the 7-bit or 10-bit address of the I2C slave
* on the bus.
*
* Returns BitBangI2C::ACK or BitBangI2C::NACK to indicate whether the
* read operation was acknowledged by the slave or not.
*
* \sa startWrite()
*/
BitBangI2C::ack_t BitBangI2C::startRead(unsigned int address)
{
start();
if (address < 0x80) {
// 7-bit address.
return write((uint8_t)((address << 1) | I2C_READ));
} else {
// 10-bit address.
if (write((uint8_t)(((address >> 7) & 0x06)) | I2C_READ10) == NACK)
return NACK;
return write((uint8_t)address);
}
}
/**
* \brief Writes a single byte \a value on the I2C bus.
*
* Returns BitBangI2C::ACK or BitBangI2C::NACK to indicate whether the
* slave acknowledged the byte or not.
*/
BitBangI2C::ack_t BitBangI2C::write(uint8_t value)
void BitBangI2C::write(uint8_t value)
{
uint8_t mask = 0x80;
while (mask != 0) {
writeBit((value & mask) != 0);
mask >>= 1;
}
return readBit();
if (readBit()) // 0: ACK, 1: NACK
acked = false;
}
/**
* \brief Reads a single byte from the I2C bus.
*
* If \a ack is BitBangI2C::ACK, then the byte is acknowledged. Otherwise
* the byte will not be acknowledged.
*/
uint8_t BitBangI2C::read(ack_t ack)
bool BitBangI2C::endWrite()
{
stop();
return acked;
}
bool BitBangI2C::startRead(unsigned int address, unsigned int count)
{
start();
inWrite = false;
if (address < 0x80) {
// 7-bit address.
write((uint8_t)((address << 1) | I2C_READ));
} else {
// 10-bit address.
write((uint8_t)(((address >> 7) & 0x06)) | I2C_READ10);
write((uint8_t)address);
}
if (!acked) {
readCount = 0;
return false;
}
readCount = count;
return true;
}
unsigned int BitBangI2C::available()
{
return readCount;
}
uint8_t BitBangI2C::read()
{
uint8_t value = 0;
for (uint8_t bit = 0; bit < 8; ++bit)
value = (value << 1) | readBit();
writeBit(ack);
if (readCount > 1) {
// More bytes left to read - send an ACK.
writeBit(false);
--readCount;
} else {
// Last byte - send the NACK and a stop condition.
writeBit(true);
stop();
readCount = 0;
}
return value;
}

27
libraries/I2C/BitBangI2C.h
View File

@ -23,31 +23,32 @@
#ifndef BitBangI2C_h
#define BitBangI2C_h
#include <inttypes.h>
#include "I2CMaster.h"
class BitBangI2C {
class BitBangI2C : public I2CMaster {
public:
BitBangI2C(uint8_t dataPin, uint8_t clockPin);
typedef bool ack_t;
unsigned int maxTransferSize() const;
static const ack_t ACK = false;
static const ack_t NACK = true;
void startWrite(unsigned int address);
void write(uint8_t value);
bool endWrite();
void start();
void stop();
ack_t startWrite(unsigned int address);
ack_t startRead(unsigned int address);
ack_t write(uint8_t value);
uint8_t read(ack_t ack = ACK);
bool startRead(unsigned int address, unsigned int count);
unsigned int available();
uint8_t read();
private:
uint8_t _dataPin;
uint8_t _clockPin;
bool started;
bool acked;
bool inWrite;
unsigned int readCount;
void start();
void stop();
void writeBit(bool bit);
bool readBit();
};

89
libraries/I2C/I2CMaster.cpp Normal file
View File

@ -0,0 +1,89 @@
/*
* Copyright (C) 2012 Southern Storm Software, Pty Ltd.
*
* Permission is hereby granted, free of charge, to any person obtaining a
* copy of this software and associated documentation files (the "Software"),
* to deal in the Software without restriction, including without limitation
* the rights to use, copy, modify, merge, publish, distribute, sublicense,
* and/or sell copies of the Software, and to permit persons to whom the
* Software is furnished to do so, subject to the following conditions:
*
* The above copyright notice and this permission notice shall be included
* in all copies or substantial portions of the Software.
*
* THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS
* OR IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
* FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE
* AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER
* LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING
* FROM, OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER
* DEALINGS IN THE SOFTWARE.
*/
#include "I2CMaster.h"
/**
* \class I2CMaster I2CMaster.h <I2CMaster.h>
* \brief Abstract base class for I2C master implementations.
*
* \sa I2CMaster
*/
/**
* \fn unsigned int I2CMaster::maxTransferSize() const
* \brief Returns the maximum number of bytes that can be read or written in a single request by this bus master.
*/
/**
* \fn void I2CMaster::startWrite(unsigned int address)
* \brief Starts a write operation by sending a start condition and the I2C control byte.
*
* The \a address must be the 7-bit or 10-bit address of the I2C slave
* on the bus.
*
* \sa write(), endWrite(), startRead()
*/
/**
* \fn void I2CMaster::write(uint8_t value)
* \brief Writes a single byte \a value on the I2C bus.
*
* \sa startWrite(), endWrite()
*/
/**
* \fn bool I2CMaster::endWrite()
* \brief Ends the current write operation.
*
* Returns true if the write operation was acknowledged; false otherwise.
*
* \sa startWrite(), write()
*/
/**
* \fn bool I2CMaster::startRead(unsigned int address, unsigned int count)
* \brief Starts a read operation for \a count bytes by sending the start condition and the I2C control byte.
*
* The \a address must be the 7-bit or 10-bit address of the I2C slave
* on the bus.
*
* Returns true if the read request was acknowledged by the I2C slave
* or false otherwise. If true, this function should be followed by
* \a count calls to read() to fetch the bytes.
*
* \sa available(), read(), startWrite()
*/
/**
* \fn unsigned int I2CMaster::available()
* \brief Returns the number of bytes that are still available for reading.
*
* \sa startRead(), read()
*/
/**
* \fn uint8_t I2CMaster::read()
* \brief Reads a single byte from the I2C bus.
*
* \sa startRead(), available()
*/

41
libraries/I2C/I2CMaster.h Normal file
View File

@ -0,0 +1,41 @@
/*
* Copyright (C) 2012 Southern Storm Software, Pty Ltd.
*
* Permission is hereby granted, free of charge, to any person obtaining a
* copy of this software and associated documentation files (the "Software"),
* to deal in the Software without restriction, including without limitation
* the rights to use, copy, modify, merge, publish, distribute, sublicense,
* and/or sell copies of the Software, and to permit persons to whom the
* Software is furnished to do so, subject to the following conditions:
*
* The above copyright notice and this permission notice shall be included
* in all copies or substantial portions of the Software.
*
* THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS
* OR IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
* FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE
* AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER
* LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING
* FROM, OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER
* DEALINGS IN THE SOFTWARE.
*/
#ifndef I2CMaster_h
#define I2CMaster_h
#include <inttypes.h>
class I2CMaster {
public:
virtual unsigned int maxTransferSize() const = 0;
virtual void startWrite(unsigned int address);
virtual void write(uint8_t value) = 0;
virtual bool endWrite() = 0;
virtual bool startRead(unsigned int address, unsigned int count) = 0;
virtual unsigned int available() = 0;
virtual uint8_t read() = 0;
};
#endif

130
libraries/RTC/DS1307RTC.cpp
View File

@ -21,7 +21,7 @@
*/
#include "DS1307RTC.h"
#include "../I2C/BitBangI2C.h"
#include "../I2C/I2CMaster.h"
#include <WProgram.h>
/**
@ -76,38 +76,29 @@
*
* \sa hasUpdates()
*/
DS1307RTC::DS1307RTC(BitBangI2C &bus, uint8_t oneHzPin)
DS1307RTC::DS1307RTC(I2CMaster &bus, uint8_t oneHzPin)
: _bus(&bus)
, _oneHzPin(oneHzPin)
, prevOneHz(false)
, _isRealTime(true)
{
// Make sure the CH bit in register 0 is off or the clock won't update.
if (_bus->startWrite(DS1307_I2C_ADDRESS) == BitBangI2C::ACK) {
_bus->write(DS1307_SECOND);
_bus->startRead(DS1307_I2C_ADDRESS);
uint8_t value = _bus->read(BitBangI2C::NACK);
_bus->stop();
if ((value & 0x80) != 0) {
_bus->startWrite(DS1307_I2C_ADDRESS);
_bus->write(DS1307_SECOND);
_bus->write(value & 0x7F);
_bus->stop();
}
_bus->startWrite(DS1307_I2C_ADDRESS);
_bus->write(DS1307_SECOND);
if (_bus->startRead(DS1307_I2C_ADDRESS, 1)) {
uint8_t value = _bus->read();
if ((value & 0x80) != 0)
writeRegister(DS1307_SECOND, value & 0x7F);
} else {
// Did not get an acknowledgement from the RTC chip.
_isRealTime = false;
_bus->stop();
}
// Turn on the 1 Hz square wave signal if required.
if (oneHzPin != 255 && _isRealTime) {
pinMode(oneHzPin, INPUT);
digitalWrite(oneHzPin, HIGH);
_bus->startWrite(DS1307_I2C_ADDRESS);
_bus->write(DS1307_CONTROL);
_bus->write(0x10);
_bus->stop();
writeRegister(DS1307_CONTROL, 0x10);
}
// Initialize the alarms in the RTC chip's NVRAM.
@ -168,11 +159,16 @@ void DS1307RTC::readTime(RTCTime *value)
if (_isRealTime) {
_bus->startWrite(DS1307_I2C_ADDRESS);
_bus->write(DS1307_SECOND);
_bus->startRead(DS1307_I2C_ADDRESS);
value->second = fromBCD(_bus->read() & 0x7F);
value->minute = fromBCD(_bus->read());
value->hour = fromHourBCD(_bus->read(BitBangI2C::NACK));
_bus->stop();
if (_bus->startRead(DS1307_I2C_ADDRESS, 3)) {
value->second = fromBCD(_bus->read() & 0x7F);
value->minute = fromBCD(_bus->read());
value->hour = fromHourBCD(_bus->read());
} else {
// RTC chip is not responding.
value->second = 0;
value->minute = 0;
value->hour = 0;
}
} else {
RTC::readTime(value);
}
@ -186,11 +182,16 @@ void DS1307RTC::readDate(RTCDate *value)
}
_bus->startWrite(DS1307_I2C_ADDRESS);
_bus->write(DS1307_DATE);
_bus->startRead(DS1307_I2C_ADDRESS);
value->day = fromBCD(_bus->read());
value->month = fromBCD(_bus->read());
value->year = fromBCD(_bus->read(BitBangI2C::NACK)) + 2000;
_bus->stop();
if (_bus->startRead(DS1307_I2C_ADDRESS, 3)) {
value->day = fromBCD(_bus->read());
value->month = fromBCD(_bus->read());
value->year = fromBCD(_bus->read()) + 2000;
} else {
// RTC chip is not responding.
value->day = 1;
value->month = 1;
value->year = 2012;
}
}
inline uint8_t toBCD(uint8_t value)
@ -206,7 +207,7 @@ void DS1307RTC::writeTime(const RTCTime *value)
_bus->write(toBCD(value->second));
_bus->write(toBCD(value->minute));
_bus->write(toBCD(value->hour)); // Changes mode to 24-hour clock.
_bus->stop();
_bus->endWrite();
} else {
RTC::writeTime(value);
}
@ -220,7 +221,7 @@ void DS1307RTC::writeDate(const RTCDate *value)
_bus->write(toBCD(value->day));
_bus->write(toBCD(value->month));
_bus->write(toBCD(value->year % 100));
_bus->stop();
_bus->endWrite();
} else {
RTC::writeDate(value);
}
@ -231,11 +232,16 @@ void DS1307RTC::readAlarm(uint8_t alarmNum, RTCAlarm *value)
if (_isRealTime) {
_bus->startWrite(DS1307_I2C_ADDRESS);
_bus->write(DS1307_ALARMS + alarmNum * DS1307_ALARM_SIZE);
_bus->startRead(DS1307_I2C_ADDRESS);
value->hour = fromBCD(_bus->read());
value->minute = fromBCD(_bus->read());
value->flags = _bus->read(BitBangI2C::NACK);
_bus->stop();
if (_bus->startRead(DS1307_I2C_ADDRESS, 3)) {
value->hour = fromBCD(_bus->read());
value->minute = fromBCD(_bus->read());
value->flags = _bus->read();
} else {
// RTC chip is not responding.
value->hour = 0;
value->minute = 0;
value->flags = 0;
}
} else {
RTC::readAlarm(alarmNum, value);
}
@ -249,7 +255,7 @@ void DS1307RTC::writeAlarm(uint8_t alarmNum, const RTCAlarm *value)
_bus->write(toBCD(value->hour));
_bus->write(toBCD(value->minute));
_bus->write(value->flags);
_bus->stop();
_bus->endWrite();
} else {
RTC::writeAlarm(alarmNum, value);
}
@ -257,37 +263,23 @@ void DS1307RTC::writeAlarm(uint8_t alarmNum, const RTCAlarm *value)
uint8_t DS1307RTC::readByte(uint8_t offset)
{
if (_isRealTime) {
_bus->startWrite(DS1307_I2C_ADDRESS);
_bus->write(DS1307_NVRAM + offset);
_bus->startRead(DS1307_I2C_ADDRESS);
uint8_t value = _bus->read(BitBangI2C::NACK);
_bus->stop();
return value;
} else {
if (_isRealTime)
return readRegister(DS1307_NVRAM + offset);
else
return RTC::readByte(offset);
}
}
void DS1307RTC::writeByte(uint8_t offset, uint8_t value)
{
if (_isRealTime) {
_bus->startWrite(DS1307_I2C_ADDRESS);
_bus->write(DS1307_NVRAM + offset);
_bus->write(value);
_bus->stop();
} else {
if (_isRealTime)
writeRegister(DS1307_NVRAM + offset, value);
else
RTC::writeByte(offset, value);
}
}
void DS1307RTC::initAlarms()
{
_bus->startWrite(DS1307_I2C_ADDRESS);
_bus->write(DS1307_ALARM_MAGIC);
_bus->startRead(DS1307_I2C_ADDRESS);
uint8_t value = _bus->read(BitBangI2C::NACK);
_bus->stop();
uint8_t value = readRegister(DS1307_ALARM_MAGIC);
if (value != (0xB0 + ALARM_COUNT)) {
// This is the first time we have used this clock chip,
// so initialize all alarms to their default state.
@ -297,10 +289,7 @@ void DS1307RTC::initAlarms()
alarm.flags = 0;
for (uint8_t index = 0; index < ALARM_COUNT; ++index)
writeAlarm(index, &alarm);
_bus->startWrite(DS1307_I2C_ADDRESS);
_bus->write(DS1307_ALARM_MAGIC);
_bus->write(0xB0 + ALARM_COUNT);
_bus->stop();
writeRegister(DS1307_I2C_ADDRESS, 0xB0 + ALARM_COUNT);
// Also clear the rest of NVRAM so that it is in a known state.
// Otherwise we'll have whatever garbage was present at power-on.
@ -308,6 +297,23 @@ void DS1307RTC::initAlarms()
_bus->write(DS1307_NVRAM);
for (uint8_t index = DS1307_NVRAM; index < DS1307_ALARMS; ++index)
_bus->write(0);
_bus->stop();
_bus->endWrite();
}
}
uint8_t DS1307RTC::readRegister(uint8_t reg)
{
_bus->startWrite(DS1307_I2C_ADDRESS);
_bus->write(reg);
if (!_bus->startRead(DS1307_I2C_ADDRESS, 1))
return 0; // RTC chip is not responding.
return _bus->read();
}
bool DS1307RTC::writeRegister(uint8_t reg, uint8_t value)
{
_bus->startWrite(DS1307_I2C_ADDRESS);
_bus->write(reg);
_bus->write(value);
return _bus->endWrite();
}

9
libraries/RTC/DS1307RTC.h
View File

@ -25,11 +25,11 @@
#include "RTC.h"
class BitBangI2C;
class I2CMaster;
class DS1307RTC : public RTC {
public:
DS1307RTC(BitBangI2C &bus, uint8_t oneHzPin = 255);
DS1307RTC(I2CMaster &bus, uint8_t oneHzPin = 255);
~DS1307RTC();
bool isRealTime() const { return _isRealTime; }
@ -49,12 +49,15 @@ public:
void writeByte(uint8_t offset, uint8_t value);
private:
BitBangI2C *_bus;
I2CMaster *_bus;
uint8_t _oneHzPin;
bool prevOneHz;
bool _isRealTime;
void initAlarms();
uint8_t readRegister(uint8_t reg);
bool writeRegister(uint8_t reg, uint8_t value);
};
#endif