ATMEGA165-16AU Atmel, ATMEGA165-16AU Datasheet - Page 23

• Manufacturer Part Number: ATMEGA165-16AU
• Description: IC AVR MCU 16K 16MHZ 64TQFP
• Manufacturer: Atmel
• Series: AVR® ATmegar

Specifications of ATMEGA165-16AU

• Core Processor: AVR
• Core Size: 8-Bit
• Speed: 16MHz
• Connectivity: SPI, UART/USART, USI
• Peripherals: Brown-out Detect/Reset, POR, PWM, WDT
• Number Of I /o: 54
• Program Memory Size: 16KB (8K 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 8x10b
• Oscillator Type: Internal
• Operating Temperature: -40°C ~ 85°C
• Package / Case: 64-TQFP, 64-VQFP
• Lead Free Status / RoHS Status: Lead free / RoHS Compliant

System Clock and
Clock Options
Clock Systems and their
Distribution
CPU Clock – clk
I/O Clock – clk
Flash Clock – clk
Asynchronous Timer Clock –
clk
2573G–AVR–07/09
ASY
I/O
CPU
FLASH
Figure 11 presents the principal clock systems in the AVR and their distribution. All of
the clocks need not be active at a given time. In order to reduce power consumption, the
clocks to modules not being used can be halted by using different sleep modes, as
described in “Power Management and Sleep Modes” on page 32. The clock systems
are detailed below.
Figure 11. Clock Distribution
The CPU clock is routed to parts of the system concerned with operation of the AVR
core. Examples of such modules are the General Purpose Register File, the Status Reg-
ister and the data memory holding the Stack Pointer. Halting the CPU clock inhibits the
core from performing general operations and calculations.
The I/O clock is used by the majority of the I/O modules, like Timer/Counters, SPI, and
USART. The I/O clock is also used by the External Interrupt module, but note that some
external interrupts are detected by asynchronous logic, allowing such interrupts to be
detected even if the I/O clock is halted. Also note that start condition detection in the USI
module is carried out asynchronously when clk
detection in all sleep modes.
The Flash clock controls operation of the Flash interface. The Flash clock is usually
active simultaneously with the CPU clock.
The Asynchronous Timer clock allows the Asynchronous Timer/Counter to be clocked
directly from an external clock or an external 32 kHz clock crystal. The dedicated clock
domain allows using this Timer/Counter as a real-time counter even when the device is
in sleep mode.
Asynchronous
Timer/Counter
Timer/Counter
Oscillator
General I/O
Modules
External Clock
clk
clk
ASY
I/O
System Clock
Control Unit
AVR Clock
Multiplexer
Prescaler
Clock
Oscillator
Crystal
Source clock
I/O
CPU Core
clk
clk
Reset Logic
is halted, enabling USI start condition
CPU
FLASH
Crystal Oscillator
Watchdog clock
Low-frequency
ATmega165/V
Watchdog Timer
RAM
Watchdog
Oscillator
Calibrated RC
Flash and
EEPROM
Oscillator
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