ATMEGA169 ATMEL [ATMEL Corporation], ATMEGA169 Datasheet - Page 20

• Manufacturer Part Number: ATMEGA169
• Description: 8-bit Microcontroller with 16K Bytes In-System Programmable Flash
• Manufacturer: ATMEL [ATMEL Corporation]

20
ATmega169/V
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 inter-
rupts globally) 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 com-
mand to finish.
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
out
; Write data (r16) to Data Register
out
; Write logical one to EEMWE
sbi
; Start eeprom write by setting EEWE
sbi
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);
;
EEARH, r18
EEARL, r17
EEDR,r16
EECR,EEMWE
EECR,EEWE
2514P–AVR–07/06