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avr_eeprom - <avr/eeprom.h>: EEPROM handling
Contents
Detailed Description
#include <avr/eeprom.h>
This header file declares the interface to some simple library routines suitable for handling the data
EEPROM contained in the AVR microcontrollers. The implementation uses a simple polled mode interface.
Applications that require interrupt-controlled EEPROM access to ensure that no time will be wasted in
spinloops will have to deploy their own implementation.
Notes:
• In addition to the write functions there is a set of update ones. This functions read each byte first
and skip the burning if the old value is the same with new. The scaning direction is from high address
to low, to obtain quick return in common cases.
• All of the read/write functions first make sure the EEPROM is ready to be accessed. Since this may
cause long delays if a write operation is still pending, time-critical applications should first poll
the EEPROM e. g. using eeprom_is_ready() before attempting any actual I/O. But this functions does not
wait until SELFPRGEN in SPMCSR becomes zero. Do this manually, if your softwate contains the Flash
burning.
• As these functions modify IO registers, they are known to be non-reentrant. If any of these functions
are used from both, standard and interrupt context, the applications must ensure proper protection
(e.g. by disabling interrupts before accessing them).
• All write functions force erase_and_write programming mode.
• For Xmega the EEPROM start address is 0, like other architectures. The reading functions add the 0x2000
value to use EEPROM mapping into data space.
Function Documentation
voideeprom_read_block(void*__dst,constvoid*__src,size_t__n)
Read a block of __n bytes from EEPROM address __src to SRAM __dst.
uint8_teeprom_read_byte(constuint8_t*__p)
Read one byte from EEPROM address __p.
doubleeeprom_read_double(constdouble*__p)
Read one double value (little endian) from EEPROM address __p.
uint32_teeprom_read_dword(constuint32_t*__p)
Read one 32-bit double word (little endian) from EEPROM address __p.
floateeprom_read_float(constfloat*__p)
Read one float value (little endian) from EEPROM address __p.
longdoubleeeprom_read_long_double(constlongdouble*__p)
Read one long double value (little endian) from EEPROM address __p.
uint64_teeprom_read_qword(constuint64_t*__p)
Read one 64-bit quad word (little endian) from EEPROM address __p.
uint16_teeprom_read_word(constuint16_t*__p)
Read one 16-bit word (little endian) from EEPROM address __p.
voideeprom_update_block(constvoid*__src,void*__dst,size_t__n)
Update a block of __n bytes at EEPROM address __dst from __src.
Note
The argument order is mismatch with common functions like strcpy().
voideeprom_update_byte(uint8_t*__p,uint8_t__value)
Update a byte __value at EEPROM address __p.
voideeprom_update_double(double*__p,double__value)
Update a double __value at EEPROM address __p.
voideeprom_update_dword(uint32_t*__p,uint32_t__value)
Update a 32-bit double word __value at EEPROM address __p.
voideeprom_update_float(float*__p,float__value)
Update a float __value at EEPROM address __p.
voideeprom_update_long_double(longdouble*__p,longdouble__value)
Update a long double __value at EEPROM address __p.
voideeprom_update_qword(uint64_t*__p,uint64_t__value)
Update a 64-bit quad word __value at EEPROM address __p.
voideeprom_update_word(uint16_t*__p,uint16_t__value)
Update a word __value at EEPROM address __p.
voideeprom_write_block(constvoid*__src,void*__dst,size_t__n)
Write a block of __n bytes to EEPROM address __dst from __src.
Note
The argument order is mismatch with common functions like strcpy().
voideeprom_write_byte(uint8_t*__p,uint8_t__value)
Write a byte __value to EEPROM address __p.
voideeprom_write_double(double*__p,double__value)
Write a double __value to EEPROM address __p.
voideeprom_write_dword(uint32_t*__p,uint32_t__value)
Write a 32-bit double word __value to EEPROM address __p.
voideeprom_write_float(float*__p,float__value)
Write a float __value to EEPROM address __p.
voideeprom_write_long_double(longdouble*__p,longdouble__value)
Write a long double __value to EEPROM address __p.
voideeprom_write_qword(uint64_t*__p,uint64_t__value)
Write a 64-bit quad word __value to EEPROM address __p.
voideeprom_write_word(uint16_t*__p,uint16_t__value)
Write a word __value to EEPROM address __p.
Macro Definition Documentation
#define__EEGET(var,addr)(var)=eeprom_read_byte((constuint8_t*)(addr))
Read a byte from EEPROM. Compatibility define for IAR C.
#define__EEPUT(addr,val)eeprom_write_byte((uint8_t*)(addr),(uint8_t)(val))
Write a byte to EEPROM. Compatibility define for IAR C.
#define_EEGET(var,addr)(var)=eeprom_read_byte((constuint8_t*)(addr))
Read a byte from EEPROM. Compatibility define for IAR C.
#define_EEPUT(addr,val)eeprom_write_byte((uint8_t*)(addr),(uint8_t)(val))
Write a byte to EEPROM. Compatibility define for IAR C.
#defineEEMEM__attribute__((__section__('.eeprom')))
Attribute expression causing a variable to be allocated within the .eeprom section.
#defineeeprom_busy_wait()do{}while(!eeprom_is_ready())
Loops until the eeprom is no longer busy.
Returns
Nothing.
#defineeeprom_is_ready()Returns
1 if EEPROM is ready for a new read/write operation, 0 if not.
Name
avr_eeprom - <avr/eeprom.h>: EEPROM handling
Synopsis
Macros
#define EEMEM __attribute__((__section__('.eeprom')))
#define eeprom_is_ready()
#define eeprom_busy_wait() do {} while (!eeprom_is_ready())
Functionsuint8_teeprom_read_byte (const uint8_t *__p)
uint16_teeprom_read_word (const uint16_t *__p)
uint32_teeprom_read_dword (const uint32_t *__p)
uint64_teeprom_read_qword (const uint64_t *__p)
float eeprom_read_float (const float *__p)
double eeprom_read_double (const double *__p)
long double eeprom_read_long_double (const long double *__p)
void eeprom_read_block (void *__dst, const void *__src, size_t __n)
void eeprom_write_byte (uint8_t *__p, uint8_t __value)
void eeprom_write_word (uint16_t *__p, uint16_t __value)
void eeprom_write_dword (uint32_t *__p, uint32_t __value)
void eeprom_write_qword (uint64_t *__p, uint64_t __value)
void eeprom_write_float (float *__p, float __value)
void eeprom_write_double (double *__p, double __value)
void eeprom_write_long_double (long double *__p, long double __value)
void eeprom_write_block (const void *__src, void *__dst, size_t __n)
void eeprom_update_byte (uint8_t *__p, uint8_t __value)
void eeprom_update_word (uint16_t *__p, uint16_t __value)
void eeprom_update_dword (uint32_t *__p, uint32_t __value)
void eeprom_update_qword (uint64_t *__p, uint64_t __value)
void eeprom_update_float (float *__p, float __value)
void eeprom_update_double (double *__p, double __value)
void eeprom_update_long_double (long double *__p, long double __value)
void eeprom_update_block (const void *__src, void *__dst, size_t __n)
IARCcompatibilitydefines
#define _EEPUT(addr, val) eeprom_write_byte ((uint8_t *)(addr), (uint8_t)(val))
#define __EEPUT(addr, val) eeprom_write_byte ((uint8_t *)(addr), (uint8_t)(val))
#define _EEGET(var, addr) (var) = eeprom_read_byte ((const uint8_t *)(addr))
#define __EEGET(var, addr) (var) = eeprom_read_byte ((const uint8_t *)(addr))
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