cI2C
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 tagets (Uno, Nano, Mega...)
- you may prefer this one when:
- working on AVR targets
- interrupts are not needed
- you may prefer this one when:
- 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)
- you would have to use this one when:
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 initialised with appropriate speed:
- use I2C_init(speed): speed can be choosen from I2C_SPEED enum for convenience, or passing an integer as parameter
- On the other hand, Slave(s) have to be defined and initialised too:
- use I2C_SLAVE typedef to declare slaves structs
- use I2C_slave_init(pSlave, addr, regsize)
- pSlave is a pointer to the slave struct to initialise
- addr is the slave I2C address (don't shift addr, lib takes care of that)
- regsize is the width of internal slave registers (to be choosen 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 is a pointer to the slave declaration to initialise
- pFunc is a pointer to the Read or Write bypass function
- rw can be choosen from I2C_RW enum (wr=0, rd=1)
- use I2C_slave_set_rw_func(pSlave, pFunc, rw)
After all inits are done, the lib can basically be used this way:
- I2C_read(pSlave, regaddr, pData, bytes)
- pSlave is a pointer to the slave struct to read from
- regaddr is the start address to read from
- pData is a 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 is a pointer to the slave struct to write to
- regaddr is the start address to write to
- pData is a 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 dependant (and will probably only work on FUJITSU devices))
- ci2c_master_write.ino: Write some bytes to FRAM and compare them with what's read afterwards
- ci2c_master_read.ino: Read some bytes in FRAM
- ci2c_advanced.ino: Redirecting slave write & read functions (to custom functions following typedef)
Doxygen doc can be generated for the library using doxyfile
Links:
Feel free to share your thoughts @ xgarmanboziax@gmail.com about:
- issues encountered
- optimisations
- improvements & new functionalities
cI2C
WireWrapper