https://github.com/smfsw/ci2c
Arduino Hardware I2C for AVR (plain c)
https://github.com/smfsw/ci2c
arduino arduino-library avr i2c-bus
Last synced: 9 months ago
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Arduino Hardware I2C for AVR (plain c)
- Host: GitHub
- URL: https://github.com/smfsw/ci2c
- Owner: SMFSW
- License: mit
- Created: 2017-01-16T18:18:01.000Z (over 9 years ago)
- Default Branch: master
- Last Pushed: 2025-04-30T21:26:18.000Z (about 1 year ago)
- Last Synced: 2025-04-30T22:32:26.035Z (about 1 year ago)
- Topics: arduino, arduino-library, avr, i2c-bus
- Language: C
- Size: 694 KB
- Stars: 5
- Watchers: 3
- Forks: 1
- Open Issues: 0
-
Metadata Files:
- Readme: README.md
- License: LICENSE
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README
# cI2C
[](https://github.com/SMFSW)
[](LICENSE)
[](https://www.codefactor.io/repository/github/smfsw/ci2c)
[](https://smfsw.github.io/cI2C)
[](ReleaseNotes.md)
Arduino Hardware I2C for AVR (plain c)
Hardware I2C library for AVR MCUs (lib intended for I2C protocols development in c, for easier ports to other MCUs)
## Library choice
* cI2C library implements I2C bus for AVR targets (Uno, Nano, Mega...)
* you may prefer this one when:
* working on AVR targets
* interrupts are not needed
* WireWrapper implements I2C bus for every platform that includes Wire library
* you would have to use this one when:
* working on non-AVR targets
* portability is needed (using Wire library)
No refactoring is required when switching between **cI2C** & **WireWrapper** libs;
Both libs share same Typedefs, Functions & Parameters.
## Notes
* cI2C is written in plain c (intentionally)
* cI2C does not use any interrupt (yet, but soon will have to)
* cI2C is designed to act as bus Master (Slave mode will be considered in future releases)
* cI2C is set to work on AVR targets only
* for other targets, you may use **WireWrapper** instead (will be using Wire)
## Usage
This library is intended to be able to work with multiple slaves connected on the same I2C bus.
Thus, the I2C bus and Slaves are defined separately.
* On one hand, I2C bus has to be initialized with appropriate speed:
* use `I2C_init(speed)`: speed can be chosen from `I2C_SPEED` enum for convenience, or passing an integer as parameter
* On the other hand, Slave(s) have to be defined and initialized too:
* use `I2C_SLAVE` typedef to declare slaves structs
* use `I2C_slave_init(pSlave, addr, regsize)`
* `pSlave`: pointer to the slave struct to initialize
* `addr`: slave I2C address (don't shift addr, lib takes care of that)
* `regsize`: width of internal slave registers (to be chosen from `I2C_INT_SIZE`)
* in case you need to use custom R/W procedures for a particular slave:
* use `I2C_slave_set_rw_func(pSlave, pFunc, rw)`
* `pSlave`: pointer to the slave declaration to initialize
* `pFunc`: pointer to the Read or Write bypass function
* `rw`: can be chosen from `I2C_RW` enum (wr=0, rd=1)
After all inits are done, the lib can basically be used this way:
* `I2C_read(pSlave, regaddr, pData, bytes)`
* `pSlave`: pointer to the slave struct to read from
* `regaddr`: start address to read from
* `pData`: pointer to the place where datas read will be stored
* `bytes`: number of bytes to read from slave
* returns `true` if read is ok, `false` otherwise
* `I2C_write(pSlave, regaddr, pData, bytes)`
* `pSlave`: pointer to the slave struct to write to
* `regaddr`: start address to write to
* `pData`: pointer to the block of datas to write to slave
* `bytes`: number of bytes to write to slave
* returns `true` if write is ok, `false` otherwise
## Examples included
following examples should work with any I2C EEPROM/FRAM with address 0x50
(yet function to get Chip ID are device dependent (and will probably only work on FUJITSU devices))
* [ci2c_master_write.ino](examples/ci2c_master_write/ci2c_master_write.ino): Write some bytes to FRAM and compare them with what's read afterwards
* [ci2c_master_read.ino](examples/ci2c_master_read/ci2c_master_read.ino): Read some bytes in FRAM
* [ci2c_advanced.ino](examples/ci2c_advanced/ci2c_advanced.ino): Redirecting slave write & read functions (to custom functions following typedef)
## See also
**cI2C**
* [cI2C github](https://github.com/SMFSW/cI2C) - C implementation of this library
**WireWrapper**
* [WireWrapper github](https://github.com/SMFSW/WireWrapper) - Cpp implementation using Wire Wrapper