eLua reference manual - I2C module
Overview
This module contains functions for accessing the I2C interfaces of the eLua CPU.
IMPORTANT: right now, only master I2C mode is implemented in eLua.
Functions
speed = i2c.setup( id, speed )
Setup the I2C interface.
Arguments:
- id - the ID of the I2C interface.
- speed - the speed of the I2C interface. It can be either i2c.FAST (400KHz) or i2c.SLOW (100KHz).
Returns: the actual speed of the I2C interface.
i2c.start( id )
Send a START on the specified I2C interface.
Arguments: id - the ID of the I2C interface.
Returns: nothing.
i2c.stop( id )
Send a STOP on the specified I2C interface.
Arguments: id - the ID of the I2C interface.
Returns: nothing.
acked = i2c.address( id, address, direction )
Send an address on the I2C interface.
Arguments:
- id - the ID of the I2C interface.
- address - the address.
- direction - i2c.TRANSMITTER if the master wants to send data, or i2c.RECEIVER if the master wants to receive data.
Returns: true if the address was acknowledged by an I2C slave, false otherwise.
wrote = i2c.write( id, data1, [data2], ..., [datan] )
Writes data to a slave that already acknowledged an i2c.address call.
Arguments:
- id - the ID of the I2C interface.
- data1 - the data to send. It can be either a number between 0 and 255, a string or a table (array).
- data2 (optional) - the second data to send.
- datan (optional) - the n-th data to send.
Returns: the number of bytes actually wrote.
data = i2c.read( id, numbytes )
Reads a number of bytes from a slave that already acknowledged an i2c.address call. It acknowledges all the bytes received, except for the last one.
Arguments:
- id - the ID os the SPI interface.
- numbytes - the number of bytes to read.
Returns: a string with all the data read from the I2C interface.