ATtiny26 Atmel Corporation, ATtiny26 Datasheet - Page 23

• Manufacturer Part Number: ATtiny26
• Manufacturer: Atmel Corporation

Specifications of ATtiny26

• Flash (kbytes): 2 Kbytes
• Pin Count: 20
• Max. Operating Frequency: 16 MHz
• Cpu: 8-bit AVR
• Hardware Qtouch Acquisition: No
• Max I/o Pins: 16
• Ext Interrupts: 11
• Usb Speed: No
• Usb Interface: No
• Spi: 1
• Twi (i2c): 1
• Graphic Lcd: No
• Video Decoder: No
• Camera Interface: No
• Adc Channels: 11
• Adc Resolution (bits): 10
• Adc Speed (ksps): 15
• Analog Comparators: 1
• Resistive Touch Screen: No
• Temp. Sensor: No
• Crypto Engine: No
• Sram (kbytes): 0.12
• Eeprom (bytes): 128
• Self Program Memory: NO
• Dram Memory: No
• Nand Interface: No
• Picopower: No
• Temp. Range (deg C): -40 to 85
• I/o Supply Class: 2.7 to 5.5
• Operating Voltage (vcc): 2.7 to 5.5
• Fpu: No
• Mpu / Mmu: no / no
• Timers: 2
• Output Compare Channels: 3
• Pwm Channels: 4
• 32khz Rtc: No
• Calibrated Rc Oscillator: Yes

System Clock
and Clock
Options
Clock Systems
and their
Distribution
CPU Clock – clk
I/O Clock – clk
Flash Clock – clk
ADC Clock – clk
1477K–AVR–08/10
I/O
CPU
ADC
FLASH
Figure 20 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 Manage-
ment and Sleep Modes” on page 37. The clock systems are detailed below.
Figure 20. 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 Register 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, and USI. 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.
The Flash clock controls operation of the Flash interface. The Flash clock is usually active simul-
taneously with the CPU clock.
The ADC is provided with a dedicated clock domain. This allows halting the CPU and I/O clocks
in order to reduce noise generated by digital circuitry. This gives more accurate ADC conversion
results.
clk
Timer/Counter1
PCK
PLL
clk
PLL
External RC
General I/O
Oscillator
modules
clk
I/O
Multiplexer
External clock
Control Unit
AVR Clock
Clock
ADC
Source clock
clk
ADC
clk
Oscillator
clk
Crystal
CPU
FLASH
Reset Logic
CPU Core
Crystal Oscillator
Low-Frequency
Watchdog clock
RAM
Watchdog Timer
Watchdog
Oscillator
Calibrated RC
Flash and
EEPROM
Oscillator
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