24CXX I²C EEPROM

This is a generic class that implements 24CXX I²C EEPROMs.

Header file:

#include <hwa/ext/24cxx.h>

Interface

• define a 24CXX device:
  
  

  HW_24CXX(...) defines a 24CXX device. You must provide:

  • the I²C interface the device is connected to;
  • the slave address of the device;
  • the address size in bytes (1, 2);
  • the pagesize in bytes.
  
  Example:

#define EEPROM       HW_24CXX( interface,   twi0,   \
                               address,     0x50,   \
                               addresssize, 2,      \
                               pagesize,    8 )

The implementation of this device focuses on code size rather than on speed, so it relies on extern C functions. These functions are declared with HW_DECLARE(...) and defined with HW_IMPLEMENT(...):

HW_DECLARE( EEPROM );      // Declare the functions that implement the device

HW_IMPLEMENT( EEPROM );    // Define the functions that implement the device

• read multiple bytes from the EEPROM:

uint8_t r ;
r = hw( read,    EEPROM,
        address, a,
        size,    s,
        buffer,  b );
if (r < s)
  error();

• write multiple bytes into the EEPROM:

uint8_t r ;
r = hw( write,   EEPROM,
        address, a,
        size,    s,
        buffer,  b );
if (r < s)
  error();