ATMEGA328P-20PU Atmel, ATMEGA328P-20PU Datasheet - Page 36
ATMEGA328P-20PU
Manufacturer Part Number
ATMEGA328P-20PU
Description
Manufacturer
Atmel
Datasheet
1.ATMEGA328P-20PU.pdf
(419 pages)
Specifications of ATMEGA328P-20PU
Cpu Family
ATmega
Device Core
AVR
Device Core Size
8b
Frequency (max)
20MHz
Interface Type
SPI/TWI/USART
Program Memory Type
Flash
Program Memory Size
32KB
Total Internal Ram Size
2KB
# I/os (max)
23
Number Of Timers - General Purpose
3
Operating Supply Voltage (typ)
3.3/5V
Operating Supply Voltage (max)
5.5V
Operating Supply Voltage (min)
2.7V
On-chip Adc
6-chx10-bit
Instruction Set Architecture
RISC
Operating Temp Range
-40C to 85C
Operating Temperature Classification
Industrial
Mounting
Through Hole
Pin Count
28
Package Type
PDIP
Lead Free Status / Rohs Status
Compliant
- Current page: 36 of 419
- Download datasheet (7Mb)
ATmega48P/88P/168P
frequency of the CPU and all synchronous peripherals. clk
, clk
, clk
, and clk
are
I/O
ADC
CPU
FLASH
divided by a factor as shown in
Table 28-3 on page
313.
When switching between prescaler settings, the System Clock Prescaler ensures that no
glitches occurs in the clock system. It also ensures that no intermediate frequency is higher than
neither the clock frequency corresponding to the previous setting, nor the clock frequency corre-
sponding to the new setting. The ripple counter that implements the prescaler runs at the
frequency of the undivided clock, which may be faster than the CPU's clock frequency. Hence, it
is not possible to determine the state of the prescaler - even if it were readable, and the exact
time it takes to switch from one clock division to the other cannot be exactly predicted. From the
time the CLKPS values are written, it takes between T1 + T2 and T1 + 2 * T2 before the new
clock frequency is active. In this interval, 2 active clock edges are produced. Here, T1 is the pre-
vious clock period, and T2 is the period corresponding to the new prescaler setting.
To avoid unintentional changes of clock frequency, a special write procedure must befollowed to
change the CLKPS bits:
1. Write the Clock Prescaler Change Enable (CLKPCE) bit to one and all other bitsin
CLKPR to zero.
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.
36
8025K–AVR–10/09
Related parts for ATMEGA328P-20PU
Image
Part Number
Description
Manufacturer
Datasheet
Request
R
Part Number:
Description:
Manufacturer:
Atmel Corporation
Datasheet:
Part Number:
Description:
IC MCU AVR 32K FLASH 32QFN
Manufacturer:
Atmel
Datasheet:
Part Number:
Description:
IC MCU AVR 32K FLASH 32TQFP
Manufacturer:
Atmel
Datasheet:
Part Number:
Description:
IC MCU AVR 32K FLASH 28PDIP
Manufacturer:
Atmel
Datasheet:
Part Number:
Description:
8-bit Microcontrollers - MCU AVR 16KB FL 512B EE 1KB SRAM 20 MHZ GRN
Manufacturer:
Atmel
Part Number:
Description:
IC MCU AVR 32K FLASH 32TQFP
Manufacturer:
Atmel
Datasheet:
Part Number:
Description:
IC MCU AVR 32K FLASH 32QFN
Manufacturer:
Atmel
Datasheet:
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: