attiny167-esxz ATMEL Corporation, attiny167-esxz Datasheet - Page 23

• Manufacturer Part Number: attiny167-esxz
• Description: 8-bit Avr 8-bit Microcontroller Microcontroller With 16k Bytes In-system Programmable Flash And Lin Controller
• Manufacturer: ATMEL Corporation

4. System Clock and Clock Options
4.1
7728A–AUTO–07/08
Clock Systems and their Distribution
The ATtiny167 provides a large number of clock sources. They can be divided into two catego-
ries: internal and external. Some external clock sources can be shared with the asynchronous
timer. After reset, the clock source is determined by the CKSEL Fuses. Once the device is run-
ning, software clock switching is possible to any other clock sources.
Hardware controls are provided for clock switching management but some specific procedures
must be observed. Clock switching should be performed with caution as some settings could
result in the device having an incorrect configuration.
Figure 4-1
may not need to be active at any given time. In order to reduce power consumption, the clocks to
modules not being used can be halted by using different sleep modes or by using features of the
dynamic clock switch circuit (See
”Dynamic Clock Switch” on page
Figure 4-1.
Timer/Counter0
Asynchronous
presents the principal clock systems in the AVR and their distribution. All of the clocks
Clock Distribution
CKOUT
Fuse
General I/O
External Clock
Modules
clk
clk
ASY
I/O
PB4 / XTAL1 / CLKI
Multiplexer
30). The clock systems are detailed below.
”Power Management and Sleep Modes” on page 41
Crystal Oscillator
Control Unit
Low-frequency
AVR Clock
ADC
clk
Source Clock
Clock Switch
ADC
Prescaler
PB5 / XTAL2 / CLKO
Reset Logic
CPU Core
clk
clk
CPU
FLASH
Oscillator
Crystal
Watchdog Clock
Watchdog
Oscillator
Watchdog Timer
RAM
ATtiny167
Calibrated RC
Flash and
EEPROM
Oscillator
and
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