https://github.com/stevemarple/SoftWire

Software I2C implementation for Arduino and other Wiring-type environments
https://github.com/stevemarple/SoftWire

arduino arduino-library i2c software-i2c

Last synced: 29 days ago
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Software I2C implementation for Arduino and other Wiring-type environments

• Host: GitHub
• URL: https://github.com/stevemarple/SoftWire
• Owner: stevemarple
• License: lgpl-2.1
• Created: 2013-07-05T20:15:08.000Z (over 11 years ago)
• Default Branch: master
• Last Pushed: 2024-06-02T09:37:16.000Z (7 months ago)
• Last Synced: 2024-08-07T18:30:10.134Z (5 months ago)
• Topics: arduino, arduino-library, i2c, software-i2c
• Language: C++
• Size: 77.1 KB
• Stars: 136
• Watchers: 8
• Forks: 31
• Open Issues: 7
• Metadata Files:
  • Readme: README.md
  • License: LICENSE.txt

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README

        
# SoftWire

## Introduction

SoftWire is a software I2C implementation for Arduino and other

Wiring-type environments. It utilises the `pinMode()`,

`digitalWrite()` and `digitalRead()` functions. The pins to be used

for the serial data (SDA) and serial clock (SCL) control lines can be

defined at run-time. Alternatively it is possible to override the

functions which control the SDA and SCL lines, and read SDA and SCL,

thereby allowing direct port manipulation to be used if preferred.

Multiple objects (for multiple software I2C buses) and

clock-stretching by slave devices are supported. A timeout feature is

included to prevent lockups by faulty or missing hardware. The

microcontroller must function as the master device and multiple

masters are not supported.

Low-level functions can be used to send start, and stop signals, and

to read and write data; no buffers are required. In addition

high-level functions provide almost direct compatibility with the Wire

library. However, the user must first declare transmit and receive

buffers, and configure SoftWire to use them before the high-level

functions `beginTransmission()`, `endTransmission()`, `read()`, `write()` and

`requestFrom ()` can be used. Notify SoftWire of the buffers by calling the

`setTxBuffer()` and `setRxBuffer()` functions, passing in a pointer to a

byte or character buffer and the size of the buffer. See the [ReadDS1307](examples/ReadDS1307/ReadDS1307.ino) fort an exmaple of how this is done.

It is possible to assign (and reassign) the pins associated with SCL and SDA

at run-time using the functions `setScl()` and `setSda()`.

## Important changes for users of the v1.* library

To support the high-level functions required for compatibility with

the Wire library the original low-level `write()` function has been

renamed `llWrite()`.

The setter functions `setSdaLow()`, `setSdaHigh()`, `setSclLow()`,

`setSclHigh()`, `setReadSda()`, `setReadScl()` must be used to

override the functions which control and read the SDA and SCL signals.

The functions which actually set SCL/SDA  low/high are now named

`sclLow()`, `sdaLow()`, `sclHigh()` and `sdaHigh()`. These functions

should not be called directly in normal use but may be required to

force some devices into low-power mode.

## License

The SoftWire library is licensed with the GNU Lesser General Public

License. See LICENSE.txt for details.

## Requirements

The AsyncDelay library is required, see

[https://github.com/stevemarple/AsyncDelay](https://github.com/stevemarple/AsyncDelay)

## Contributors

* [Steve Marple](https://github.com/stevemarple)

* [Matthijs Kooijman](https://github.com/matthijskooijman)

* [Phonog](https://github.com/Phonog)

* [Tutoduino](https://github.com/tutoduino)

* [Brian Park](https://github.com/bxparks)

* [Wayne Piekarski](https://github.com/waynepiekarski)

* [nerdyscout](https://github.com/nerdyscout)

## Credits

This library is inspired by Peter Fleury's i2cmaster library.