ATMEGA8-16AC Atmel, ATMEGA8-16AC Datasheet - Page 16

• Manufacturer Part Number: ATMEGA8-16AC
• Description: IC AVR MCU 8K 16MHZ COM 32-TQFP
• Manufacturer: Atmel
• Series: AVR® ATmegar

Specifications of ATMEGA8-16AC

• Core Processor: AVR
• Core Size: 8-Bit
• Speed: 16MHz
• Connectivity: I²C, SPI, UART/USART
• Peripherals: Brown-out Detect/Reset, POR, PWM, WDT
• Number Of I /o: 23
• Program Memory Size: 8KB (4K x 16)
• Program Memory Type: FLASH
• Eeprom Size: 512 x 8
• Ram Size: 1K x 8
• Voltage - Supply (vcc/vdd): 4.5 V ~ 5.5 V
• Data Converters: A/D 8x10b
• Oscillator Type: Internal
• Operating Temperature: 0°C ~ 70°C
• Package / Case: 32-TQFP, 32-VQFP
• Lead Free Status / RoHS Status: Contains lead / RoHS non-compliant
• Other names: ATMEGA816AC

Interrupt Response
Time
16
ATmega8(L)
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 example.
The interrupt execution response for all the enabled Atmel
minimum. After four clock cycles, the Program Vector address for the actual interrupt handling
routine is executed. During this 4-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 com-
pleted 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 addi-
tion 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 (2 bytes) is popped back from the Stack, the Stack Pointer is incre-
mented by 2, and the I-bit in SREG is set.
Assembly Code Example
C Code Example
sei
sleep; enter sleep, waiting for interrupt
; note: will enter sleep before any pending
; interrupt(s)
_SEI(); /* set global interrupt enable */
_SLEEP(); /* enter sleep, waiting for interrupt */
/* note: will enter sleep before any pending interrupt(s) */
; set global interrupt enable
®
AVR
®
interrupts is four clock cycles
2486Z–AVR–02/11