AT90PWM2B-16SE ATMEL [ATMEL Corporation], AT90PWM2B-16SE Datasheet - Page 29

• Manufacturer Part Number: AT90PWM2B-16SE
• Description: 8-bit Microcontroller with 8K Bytes In-System Programmable Flash
• Manufacturer: ATMEL [ATMEL Corporation]

7.1.1
7.1.2
7.1.3
7.1.4
4317J–AVR–08/10
CPU Clock – clk
I/O Clock – clk
Flash Clock – clk
PLL Clock – clk
I/O
Figure 7-2.
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, SPI, 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.
The Flash clock controls operation of the Flash interface. The Flash clock is usually active simul-
taneously with the CPU clock.
The PLL clock allows the PSC modules to be clocked directly from a 64/32 MHz clock. A 16 MHz
clock is also derived for the CPU.
PLL
CPU
FLASH
PSC0/1/2
PLL Input
Multiplexer
PLL
Clock Distribution AT90PWM2B/3B
CLK
PLL
General I/O
Modules
clk
I/O
External Clock
Clock
Multiplexer
ADC
Control Unit
AVR Clock
clk
ADC
Source Clock
Oscillator)
(Crystal
CPU Core
clk
clk
AT90PWM2/3/2B/3B
CPU
FLASH
Reset Logic
Watchdog Clock
RAM
Oscillator
Watchdog
Watchdog Timer
Flash and
EEPROM
Calibrated RC
Oscillator
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