ATMEGA8A-PU Atmel, ATMEGA8A-PU Datasheet - Page 118

MCU AVR 8K FLASH 16MHZ 28-PDIP

ATMEGA8A-PU

Manufacturer Part Number
ATMEGA8A-PU
Description
MCU AVR 8K FLASH 16MHZ 28-PDIP
Manufacturer
Atmel
Series
AVR® ATmegar
Datasheets

Specifications of ATMEGA8A-PU

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)
2.7 V ~ 5.5 V
Data Converters
A/D 6x10b
Oscillator Type
Internal
Operating Temperature
-40°C ~ 85°C
Package / Case
28-DIP (0.300", 7.62mm)
Processor Series
ATMEGA8x
Core
AVR8
Data Bus Width
8 bit
Data Ram Size
1 KB
Interface Type
SPI, TWI, USART
Maximum Clock Frequency
16 MHz
Number Of Programmable I/os
23
Number Of Timers
3
Maximum Operating Temperature
+ 85 C
Mounting Style
Through Hole
3rd Party Development Tools
EWAVR, EWAVR-BL
Development Tools By Supplier
ATAVRDRAGON, ATSTK500, ATSTK600, ATAVRISP2, ATAVRONEKIT
Minimum Operating Temperature
- 40 C
On-chip Adc
10 bit, 6 Channel
Package
28PDIP
Device Core
AVR
Family Name
ATmega
Maximum Speed
16 MHz
Operating Supply Voltage
3.3|5 V
Controller Family/series
AVR MEGA
No. Of I/o's
23
Eeprom Memory Size
512Byte
Ram Memory Size
1KB
Cpu Speed
16MHz
Rohs Compliant
Yes
For Use With
ATSTK600 - DEV KIT FOR AVR/AVR32ATSTK500 - PROGRAMMER AVR STARTER KIT
Lead Free Status / RoHS Status
Lead free / RoHS Compliant

Available stocks

Company
Part Number
Manufacturer
Quantity
Price
Part Number:
ATMEGA8A-PU
Manufacturer:
ATMEL/爱特梅尔
Quantity:
20 000
17.9
17.9.1
8159D–AVR–02/11
Asynchronous Operation of the Timer/Counter
Asynchronous Operation of Timer/Counter2
Figure 17-11
Figure 17-11. Timer/Counter Timing Diagram, Clear Timer on Compare Match Mode, with Pres-
When Timer/Counter2 operates asynchronously, some considerations must be taken.
• Warning: When switching between asynchronous and synchronous clocking of
1. Disable the Timer/Counter2 interrupts by clearing OCIE2 and TOIE2.
2. Select clock source by setting AS2 as appropriate.
3. Write new values to TCNT2, OCR2, and TCCR2.
4. To switch to asynchronous operation: Wait for TCN2UB, OCR2UB, and TCR2UB.
5. Clear the Timer/Counter2 Interrupt Flags.
6. Enable interrupts, if needed.
• The Oscillator is optimized for use with a 32.768 kHz watch crystal. Applying an external
• When writing to one of the registers TCNT2, OCR2, or TCCR2, the value is transferred to a
• When entering Power-save mode after having written to TCNT2, OCR2, or TCCR2, the user
Timer/Counter2, the Timer Registers TCNT2, OCR2, and TCCR2 might be corrupted. A safe
procedure for switching clock source is:
clock to the TOSC1 pin may result in incorrect Timer/Counter2 operation. The CPU main
clock frequency must be more than four times the Oscillator frequency.
temporary register, and latched after two positive edges on TOSC1. The user should not
write a new value before the contents of the temporary register have been transferred to its
destination. Each of the three mentioned registers have their individual temporary register,
which means that e.g. writing to TCNT2 does not disturb an OCR2 write in progress. To
detect that a transfer to the destination register has taken place, the Asynchronous Status
Register – ASSR has been implemented.
must wait until the written register has been updated if Timer/Counter2 is used to wake up the
device. Otherwise, the MCU will enter sleep mode before the changes are effective. This is
particularly important if the Output Compare2 interrupt is used to wake up the device, since
TCNTn
(clk
(CTC)
OCRn
OCFn
clk
clk
I/O
I/O
Tn
/8)
shows the setting of OCF2 and the clearing of TCNT2 in CTC mode.
caler (f
clk_I/O
TOP - 1
/8)
TOP
TOP
BOTTOM
ATmega8A
BOTTOM + 1
118

Related parts for ATMEGA8A-PU