atmega3250v-8auatmega325v-8ai ATMEL Corporation, atmega3250v-8auatmega325v-8ai Datasheet - Page 23

• Manufacturer Part Number: atmega3250v-8auatmega325v-8ai
• Description: Atmega3250 8-bit Microcontroller With In-system Programmable Flash
• Manufacturer: ATMEL Corporation

2570L–AVR–08/07
The following code examples show one assembly and one C function for writing to the
EEPROM. The examples assume that interrupts are controlled (e.g. by disabling interrupts glo-
bally) so that no interrupts will occur during execution of these functions. The examples also
assume that no Flash Boot Loader is present in the software. If such code is present, the
EEPROM write function must also wait for any ongoing SPM command to finish.
The next code examples show assembly and C functions for reading the EEPROM. The exam-
ples assume that interrupts are controlled so that no interrupts will occur during execution of
these functions.
Assembly Code Example
C Code Example
EEPROM_write:
void EEPROM_write(unsigned int uiAddress, unsigned char ucData)
{
}
; Wait for completion of previous write
sbic EECR,EEWE
rjmp EEPROM_write
; Set up address (r18:r17) in address register
out EEARH, r18
out EEARL, r17
; Write data (r16) to Data Register
out EEDR,r16
; Write logical one to EEMWE
sbi EECR,EEMWE
; Start eeprom write by setting EEWE
sbi EECR,EEWE
ret
/* Wait for completion of previous write */
while(EECR & (1<<EEWE))
/* Set up address and Data Registers */
EEAR = uiAddress;
EEDR = ucData;
/* Write logical one to EEMWE */
EECR |= (1<<EEMWE);
/* Start eeprom write by setting EEWE */
EECR |= (1<<EEWE);
;
ATmega325/3250/645/6450
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