ATmega645 Atmel Corporation, ATmega645 Datasheet - Page 251
![no-image](/images/manufacturer_photos/0/0/79/atmel_corporation_sml.jpg)
ATmega645
Manufacturer Part Number
ATmega645
Description
Manufacturer
Atmel Corporation
Specifications of ATmega645
Flash (kbytes)
64 Kbytes
Pin Count
64
Max. Operating Frequency
16 MHz
Cpu
8-bit AVR
# Of Touch Channels
16
Hardware Qtouch Acquisition
No
Max I/o Pins
54
Ext Interrupts
17
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)
4
Eeprom (bytes)
2048
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
4
Input Capture Channels
1
Pwm Channels
4
32khz Rtc
Yes
Calibrated Rc Oscillator
Yes
Available stocks
Company
Part Number
Manufacturer
Quantity
Price
Part Number:
ATmega645-16AU
Manufacturer:
ATMEL/爱特梅尔
Quantity:
20 000
Company:
Part Number:
ATmega645-16MU
Manufacturer:
ATECH
Quantity:
729
Part Number:
ATmega645-16MU
Manufacturer:
ATMEL/爱特梅尔
Quantity:
20 000
Part Number:
ATmega6450-16AU
Manufacturer:
ATMEL/爱特梅尔
Quantity:
20 000
Company:
Part Number:
ATmega6450P-AU
Manufacturer:
Atmel
Quantity:
360
Company:
Part Number:
ATmega6450P-AUR
Manufacturer:
Atmel
Quantity:
1 500
Part Number:
ATmega6450V-8AI
Manufacturer:
ATMEL/爱特梅尔
Quantity:
20 000
Part Number:
ATmega6450V-8AU
Manufacturer:
ATMEL/爱特梅尔
Quantity:
20 000
26. Boot Loader Support – Read-While-Write Self-Programming
26.1
26.2
26.3
26.3.1
26.3.2
2570N–AVR–05/11
Features
Overview
Application and Boot Loader Flash Sections
Application Section
BLS – Boot Loader Section
•
•
•
•
•
•
•
Note:
The Boot Loader Support provides a real Read-While-Write Self-Programming mechanism for
downloading and uploading program code by the MCU itself. This feature allows flexible applica-
tion software updates controlled by the MCU using a Flash-resident Boot Loader program. The
Boot Loader program can use any available data interface and associated protocol to read code
and write (program) that code into the Flash memory, or read the code from the program mem-
ory. The program code within the Boot Loader section has the capability to write into the entire
Flash, including the Boot Loader memory. The Boot Loader can thus even modify itself, and it
can also erase itself from the code if the feature is not needed anymore. The size of the Boot
Loader memory is configurable with fuses and 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 differ-
ent levels of protection.
The Flash memory is organized in two main sections, the Application section and the Boot
Loader section (see
BOOTSZ Fuses as shown in
have different level of protection since they have different sets of Lock bits.
The Application section is the section of the Flash that is used for storing the application code.
The protection level for the Application section can be selected by the application Boot Lock bits
(Boot Lock bits 0), see
Boot Loader code since the SPM instruction is disabled when executed from the Application
section.
While the Application section is used for storing the application code, the The Boot Loader soft-
ware must be located in the BLS since the SPM instruction can initiate a programming when
executing from the BLS only. The SPM instruction can access the entire Flash, including the
BLS itself. The protection level for the Boot Loader section can be selected by the Boot Loader
Lock bits (Boot Lock bits 1), see
Read-While-Write Self-Programming
Flexible Boot Memory Size
High Security (Separate Boot Lock Bits for a Flexible Protection)
Separate Fuse to Select Reset Vector
Optimized Page
Code Efficient Algorithm
Efficient Read-Modify-Write Support
1. A page is a section in the Flash consisting of several bytes (see
used during programming. The page organization does not affect normal operation.
(1)
Size
Figure
Table 26-2 on page
Table 26-6 on page 262
26-2). The size of the different sections is configured by the
Table 26-3 on page
ATmega325/3250/645/6450
255. The Application section can never store any
255.
and
Figure
26-2. These two sections can
Table 27-10 on page
270)
251