ATmega168 Atmel Corporation, ATmega168 Datasheet - Page 272

• Manufacturer Part Number: ATmega168
• Manufacturer: Atmel Corporation

Specifications of ATmega168

• Flash (kbytes): 16 Kbytes
• Pin Count: 32
• Max. Operating Frequency: 20 MHz
• Cpu: 8-bit AVR
• # Of Touch Channels: 16
• Hardware Qtouch Acquisition: No
• Max I/o Pins: 23
• Ext Interrupts: 24
• Usb Speed: No
• Usb Interface: No
• Spi: 2
• Twi (i2c): 1
• Uart: 1
• Graphic Lcd: No
• Video Decoder: No
• Camera Interface: No
• Adc Channels: 8
• Adc Resolution (bits): 10
• Adc Speed (ksps): 15
• Analog Comparators: 1
• Resistive Touch Screen: No
• Temp. Sensor: No
• Crypto Engine: No
• Sram (kbytes): 1
• 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: 1.8 to 5.5
• Operating Voltage (vcc): 1.8 to 5.5
• Fpu: No
• Mpu / Mmu: no / no
• Timers: 3
• Output Compare Channels: 6
• Input Capture Channels: 1
• Pwm Channels: 6
• 32khz Rtc: Yes
• Calibrated Rc Oscillator: Yes

27.5
2545T–AVR–05/11
Boot loader lock bits
Figure 27-2. Memory sections.
Note:
If no Boot Loader capability is needed, the entire Flash is available for application code. The
Boot Loader has two separate sets of Boot Lock bits which can be set independently. This gives
the user a unique flexibility to select different levels of protection.
The user can select:
• To protect the entire Flash from a software update by the MCU
• To protect only the Boot Loader Flash section from a software update by the MCU
• To protect only the Application Flash section from a software update by the MCU
• Allow software update in the entire Flash
See
can be set in software and in Serial or Parallel Programming mode, but they can be cleared by a
Chip Erase command only. The general Write Lock (Lock Bit mode 2) does not control the pro-
gramming of the Flash memory by SPM instruction. Similarly, the general Read/Write Lock
(Lock Bit mode 1) does not control reading nor writing by LPM/SPM, if it is attempted.
Table 27-2 on page 273
1. The parameters in
Boot loader flash section
Application flash section
Application flash section
Boot loader flash section
Application flash section
Application flash section
Program memory
Program memory
BOOTSZ = '11'
BOOTSZ = '01'
Figure 27-2
and
0x0000
End RWW
Start NRWW
End application
Start boot loader
Flashend
0x0000
End RWW
Start NRWW
End application
Start boot loader
Flashend
Table 27-3 on page 273
are given in
Table 27-6 on page
Boot loader flash section
Application flash section
Application flash section
Boot loader flash section
Application flash section
Program memory
Program memory
BOOTSZ = '10'
BOOTSZ = '00'
for further details. The Boot Lock bits
ATmega48/88/168
281.
0x0000
End RWW
Start NRWW
End application
Start boot loader
Flashend
0x0000
End RWW, end application
Start NRWW, start boot loader
Flashend
272