18
8126F–AVR–05/12
ATtiny13A
The calibrated Oscillator is used to time the EEPROM accesses. Make sure the Oscillator fre-
quency is within the requirements described in
“OSCCAL – Oscillator Calibration Register” on
The following code examples show one assembly and one C function for erase, write, or atomic
write of the EEPROM. The examples assume that interrupts are controlled (e.g., by disabling
interrupts globally) so that no interrupts will occur during execution of these functions.
Note:
See
.
Assembly Code Example
EEPROM_write:
; Wait for completion of previous write
sbic
EECR,EEPE
rjmp
EEPROM_write
; Set Programming mode
ldi
r16, (0<<EEPM1)|(0<<EEPM0)
out
EECR, r16
; Set up address (r17) in address register
out
EEARL, r17
; Write data (r16) to data register
out
EEDR,r16
; Write logical one to EEMPE
sbi
EECR,EEMPE
; Start eeprom write by setting EEPE
sbi
EECR,EEPE
ret
C Code Example
void
EEPROM_write(
unsigned char
ucAddress,
unsigned char
ucData)
{
/*
Wait for completion of previous write
*/
while(EECR & (1<<EEPE))
;
/*
Set Programming mode */
EECR = (0<<EEPM1)|(0>>EEPM0)
/* Set up address and data registers */
EEARL = ucAddress;
EEDR = ucData;
/*
Write logical one to EEMPE */
EECR |= (1<<EEMPE);
/* Start eeprom write by setting EEPE */
EECR |= (1<<EEPE);
}