ATMEGA325A-MU Atmel, ATMEGA325A-MU Datasheet - Page 38
ATMEGA325A-MU
Manufacturer Part Number
ATMEGA325A-MU
Description
IC MCU AVR 32K FLASH 64VQFN
Manufacturer
Atmel
Series
AVR® ATmegar
Specifications of ATMEGA325A-MU
Core Processor
AVR
Core Size
8-Bit
Speed
20MHz
Connectivity
SPI, UART/USART, USI
Peripherals
Brown-out Detect/Reset, POR, PWM, WDT
Number Of I /o
54
Program Memory Size
32KB (16K x 16)
Program Memory Type
FLASH
Eeprom Size
1K x 8
Ram Size
2K x 8
Voltage - Supply (vcc/vdd)
1.8 V ~ 5.5 V
Data Converters
A/D 8x10b
Oscillator Type
Internal
Operating Temperature
-40°C ~ 85°C
Package / Case
64-VFQFN Exposed Pad
Lead Free Status / RoHS Status
Lead free / RoHS Compliant
- Current page: 38 of 680
- Download datasheet (37Mb)
38
ATmega165A/165PA/325A/325PA/3250A/3250PA/645A/645P/645
To avoid unintentional changes of clock frequency, a special write procedure must be followed
to change the CLKPS bits:
1. Write the Clock Prescaler Change Enable (CLKPCE) bit to one and all other bits in
2. Within four cycles, write the desired value to CLKPS while writing a zero to CLKPCE.
Interrupts must be disabled when changing prescaler setting to make sure the write procedure is
not interrupted.
The CKDIV8 Fuse determines the initial value of the CLKPS bits. If CKDIV8 is unprogrammed,
the CLKPS bits will be reset to “0000”. If CKDIV8 is programmed, CLKPS bits are reset to
“0011”, giving a division factor of 8 at start up. This feature should be used if the selected clock
source has a higher frequency than the maximum frequency of the device at the present operat-
ing conditions. Note that any value can be written to the CLKPS bits regardless of the CKDIV8
Fuse setting. The Application software must ensure that a sufficient division factor is chosen if
the selected clock source has a higher frequency than the maximum frequency of the device at
the present operating conditions. The device is shipped with the CKDIV8 Fuse programmed.
Table 8-14.
CLKPS3
CLKPR to zero.
0
0
0
0
0
0
0
0
1
1
1
1
1
1
1
1
Clock Prescaler Select
CLKPS2
0
0
0
0
1
1
1
1
0
0
0
0
1
1
1
1
CLKPS1
0
0
1
1
0
0
1
1
0
0
1
1
0
0
1
1
CLKPS0
0
1
0
1
0
1
0
1
0
1
0
1
0
1
0
1
Clock Division Factor
Reserved
Reserved
Reserved
Reserved
Reserved
Reserved
Reserved
128
256
16
32
64
1
2
4
8
8285B–AVR–03/11
Related parts for ATMEGA325A-MU
Image
Part Number
Description
Manufacturer
Datasheet
Request
R
Part Number:
Description:
Manufacturer:
Atmel Corporation
Datasheet:
Part Number:
Description:
Manufacturer:
ATMEL Corporation
Datasheet:
Part Number:
Description:
IC AVR MCU 32K 16MHZ 5V 44-QFN
Manufacturer:
Atmel
Datasheet:
Part Number:
Description:
IC AVR MCU 32K 16MHZ 5V 40DIP
Manufacturer:
Atmel
Datasheet:
Part Number:
Description:
IC AVR MCU 32K 16MHZ 5V 44TQFP
Manufacturer:
Atmel
Datasheet:
Part Number:
Description:
IC AVR MCU 32K 16MHZ IND 40-DIP
Manufacturer:
Atmel
Datasheet:
Part Number:
Description:
IC AVR MCU 32K 16MHZ IND 44-TQFP
Manufacturer:
Atmel
Datasheet:
Part Number:
Description:
MCU AVR 32KB FLASH 16MHZ 44TQFP
Manufacturer:
Atmel
Datasheet:
Part Number:
Description:
MCU AVR 32KB FLASH 16MHZ 44QFN
Manufacturer:
Atmel
Datasheet:
Part Number:
Description:
MCU AVR 32K FLASH 16MHZ 44-TQFP
Manufacturer:
Atmel
Datasheet:
Part Number:
Description:
IC AVR MCU 32K 16MHZ COM 40-DIP
Manufacturer:
Atmel
Datasheet:
Part Number:
Description:
IC AVR MCU 32K 16MHZ COM 44-QFN
Manufacturer:
Atmel
Datasheet:
Part Number:
Description:
IC AVR MCU 32K 16MHZ COM 44-TQFP
Manufacturer:
Atmel
Datasheet: