ATtiny25 Automotive Atmel Corporation, ATtiny25 Automotive Datasheet - Page 22

• Manufacturer Part Number: ATtiny25 Automotive
• Manufacturer: Atmel Corporation

Specifications of ATtiny25 Automotive

• Flash (kbytes): 2 Kbytes
• Pin Count: 8
• Max. Operating Frequency: 16 MHz
• Cpu: 8-bit AVR
• # Of Touch Channels: 4
• Hardware Qtouch Acquisition: No
• Max I/o Pins: 6
• Ext Interrupts: 6
• Usb Speed: No
• Usb Interface: No
• Spi: 1
• Twi (i2c): 1
• Graphic Lcd: No
• Video Decoder: No
• Camera Interface: No
• Adc Channels: 4
• Adc Resolution (bits): 10
• Adc Speed (ksps): 15
• Analog Comparators: 1
• Resistive Touch Screen: No
• Temp. Sensor: Yes
• Crypto Engine: No
• Sram (kbytes): 0.12
• Eeprom (bytes): 128
• Self Program Memory: YES
• Dram Memory: No
• Nand Interface: No
• Picopower: No
• Temp. Range (deg C): -40 to 125
• 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: 5
• Pwm Channels: 6
• 32khz Rtc: No
• Calibrated Rc Oscillator: Yes

6.1.1
6.1.2
6.1.3
6.1.4
6.1.5
22
ATtiny25/45/85
CPU Clock – clk
I/O Clock – clk
Flash Clock – clk
ADC Clock – clk
Internal PLL for Fast Peripheral Clock Generation - clk
I/O
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/Counter. 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.
The internal PLL in ATtiny25/45/85 generates a clock frequency that is 8x multiplied from a
source input. The source of the PLL input clock is the output of the internal RC oscillator having
a frequency of 8.0 MHz. Thus the output of the PLL, the fast peripheral clock is 64 MHz. The fast
peripheral clock, or a clock prescaled from that, can be selected as the clock source for
Timer/Counter1. See the
The PLL is locked on the RC oscillator and adjusting the RC oscillator via OSCCAL register will
adjust the fast peripheral clock at the same time. However, even if the RC oscillator is taken to a
higher frequency than 8 MHz, the fast peripheral clock frequency saturates at 85 MHz (worst
case) and remains oscillating at the maximum frequency. It should be noted that the PLL in this
case is not locked any longer with the RC oscillator clock.
Therefore, it is recommended not to take the OSCCAL adjustments to a higher frequency than 8
MHz in order to keep the PLL in the correct operating range. The internal PLL is enabled only
when the PLLE bit in PLLCSR is set or the PLLCK fuse is programmed (‘0’). The bit PLOCK
from PLLCSR is set when PLL is locked.
Both internal RC oscillator and PLL are switched off in power down and stand-by sleep modes.
CPU
ADC
FLASH
Figure 6-2 on page
PCK
23.
7598H–AVR–07/09