ATmega325 Atmel Corporation, ATmega325 Datasheet - Page 284
![no-image](/images/manufacturer_photos/0/0/79/atmel_corporation_sml.jpg)
ATmega325
Manufacturer Part Number
ATmega325
Description
Manufacturer
Atmel Corporation
Specifications of ATmega325
Flash (kbytes)
32 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)
2
Eeprom (bytes)
1024
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:
ATmega325-16AI
Manufacturer:
ATMEL/爱特梅尔
Quantity:
20 000
Company:
Part Number:
ATmega325-16AU
Manufacturer:
ATMEL
Quantity:
231
Part Number:
ATmega325-16AU
Manufacturer:
ATMEL/爱特梅尔
Quantity:
20 000
Part Number:
ATmega3250-16AI
Manufacturer:
ATMEL/爱特梅尔
Quantity:
20 000
Part Number:
ATmega3250-16AU
Manufacturer:
ATMEL/爱特梅尔
Quantity:
20 000
Part Number:
ATmega3250P-16AU
Manufacturer:
ATMEL/爱特梅尔
Quantity:
20 000
Figure 27-12. Serial Programming Instruction example
27.7.4
27.8
2570N–AVR–05/11
Byte 1
Programming via the JTAG Interface
SPI Serial Programming Characteristics
Load Program Memory Page (High/Low Byte)/
Load EEPROM Memory Page (page access)
Bit 15 B
Byte 2
Adr M M S S B
A
For characteristics of the SPI module see “SPI Timing Characteristics” on page 302.
Programming through the JTAG interface requires control of the four JTAG specific pins: TCK,
TMS, TDI, and TDO. Control of the reset and clock pins is not required.
To be able to use the JTAG interface, the JTAGEN Fuse must be programmed. The device is
default shipped with the fuse programmed. In addition, the JTD bit in MCUCSR must be cleared.
Alternatively, if the JTD bit is set, the external reset can be forced low. Then, the JTD bit will be
cleared after two chip clocks, and the JTAG pins are available for programming. This provides a
means of using the JTAG pins as normal port pins in Running mode while still allowing In-Sys-
tem Programming via the JTAG interface. Note that this technique can not be used when using
the JTAG pins for Boundary-scan or On-chip Debug. In these cases the JTAG pins must be ded-
icated for this purpose.
During programming the clock frequency of the TCK Input must be less than the maximum fre-
quency of the chip. The System Clock Prescaler can not be used to divide the TCK Clock Input
into a sufficiently low frequency.
As a definition in this data sheet, the LSB is shifted in and out first of all Shift Registers.
Byte 3
Adr LSB
Page Offset
0
Serial Programming Instruction
Byte 4
Program Memory/
EEPROM Memory
Page Buffer
Page N-1
Page 0
Page 1
Page 2
Byte 1
ATmega325/3250/645/6450
Page Number
Bit 15 B
Byte 2
Write Program Memory Page/
Write EEPROM Memory Page
Adr MSB
Byte 3
A A dr r L L SB B
0
Byte 4
284