ATmega8515 Atmel Corporation, ATmega8515 Datasheet - Page 34

• Manufacturer Part Number: ATmega8515
• Manufacturer: Atmel Corporation

Specifications of ATmega8515

• Flash (kbytes): 8 Kbytes
• Pin Count: 44
• Max. Operating Frequency: 16 MHz
• Cpu: 8-bit AVR
• # Of Touch Channels: 16
• Hardware Qtouch Acquisition: No
• Max I/o Pins: 35
• Ext Interrupts: 3
• Usb Speed: No
• Usb Interface: No
• Spi: 1
• Uart: 1
• Graphic Lcd: No
• Video Decoder: No
• Camera Interface: No
• Resistive Touch Screen: No
• Temp. Sensor: No
• Crypto Engine: No
• Sram (kbytes): 0.5
• Eeprom (bytes): 512
• Self Program Memory: YES
• 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
• Input Capture Channels: 1
• Pwm Channels: 3
• 32khz Rtc: No
• Calibrated Rc Oscillator: Yes

System Clock and
Clock Options
Clock Systems and their
Distribution
CPU Clock – clk
I/O Clock – clk
34
ATmega8515(L)
I/O
CPU
Figure 18 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 41. The clock systems
are detailed below.
Figure 18. 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.
External RC
General I/O
Oscillator
Modules
clk
I/O
External Clock
Control Unit
AVR Clock
Multiplexer
Clock
Source clock
CPU Core
clk
Oscillator
clk
Crystal
Reset Logic
CPU
FLASH
Watchdog clock
Crystal Oscillator
Low-frequency
Watchdog Timer
RAM
Watchdog
Oscillator
Calibrated RC
2512K–AVR–01/10
Flash and
EEPROM
Oscillator