ATTINY861A-SU Atmel, ATTINY861A-SU Datasheet - Page 14

• Manufacturer Part Number: ATTINY861A-SU
• Description: IC, MCU, 8BIT, 8K FLASH, 20SOIC
• Manufacturer: Atmel

Specifications of ATTINY861A-SU

• Controller Family/series: ATtiny
• No. Of I/o's: 16
• Eeprom Memory Size: 512Byte
• Ram Memory Size: 512Byte
• Cpu Speed: 20MHz
• No.: RoHS Compliant
• Core Size: 8bit
• Program Memory Size: 8KB
• Oscillator Type: External, Internal
• Rohs Compliant: Yes

4.7.1
14
ATtiny261A/461A/861A
Interrupt Response Time
Note:
When using the SEI instruction to enable interrupts, the instruction following SEI will be exe-
cuted before any pending interrupts, as shown in the following examples.
Note:
The interrupt execution response for all the enabled AVR interrupts is four clock cycles mini-
mum. After four clock cycles the Program Vector address for the actual interrupt handling routine
is executed. During this four clock cycle period, the Program Counter is pushed onto the Stack.
The vector is normally a jump to the interrupt routine, and this jump takes three clock cycles. If
an interrupt occurs during execution of a multi-cycle instruction, this instruction is completed
before the interrupt is served. If an interrupt occurs when the MCU is in sleep mode, the interrupt
execution response time is increased by four clock cycles. This increase comes in addition to the
start-up time from the selected sleep mode.
A return from an interrupt handling routine takes four clock cycles. During these four clock
cycles, the Program Counter (two bytes) is popped back from the Stack, the Stack Pointer is
incremented by two, and the I-bit in SREG is set.
Assembly Code Example
C Code Example
Assembly Code Example
C Code Example
in r16, SREG
cli
sbi EECR, EEMPE
sbi EECR, EEPE
out SREG, r16
char cSREG;
cSREG = SREG; /* store SREG value */
/* disable interrupts during timed sequence */
_CLI();
EECR |= (1<<EEMPE); /* start EEPROM write */
EECR |= (1<<EEPE);
SREG = cSREG; /* restore SREG value (I-bit) */
sei
sleep
_SEI();
_SLEEP();
See
See
“Code Examples” on page
“Code Examples” on page
; disable interrupts during timed sequence
; set Global Interrupt Enable
; enter sleep, waiting for interrupt
; note: will enter sleep before any pending interrupt(s)
/* set Global Interrupt Enable */
/* enter sleep, waiting for interrupt */
/* note: will enter sleep before any pending interrupt(s) */
; store SREG value
; start EEPROM write
; restore SREG value (I-bit)
6.
6.
8197B–AVR–01/10