ATMEGA328P-20PU Atmel, ATMEGA328P-20PU Datasheet - Page 111

• Manufacturer Part Number: ATMEGA328P-20PU
• Manufacturer: Atmel

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

15.2.1
8025K–AVR–10/09
Registers
Figure 15-1. 16-bit Timer/Counter Block Diagram
Note:
The Timer/Counter (TCNT1), Output Compare Registers (OCR1A/B), and Input Capture Regis-
ter (ICR1) are all 16-bit registers. Special procedures must be followed when accessing the 16-
bit registers. These procedures are described in the section
page
CPU access restrictions. Interrupt requests (abbreviated to Int.Req. in the figure) signals are all
visible in the Timer Interrupt Flag Register (TIFR1). All interrupts are individually masked with
the Timer Interrupt Mask Register (TIMSK1). TIFR1 and TIMSK1 are not shown in the figure.
The Timer/Counter can be clocked internally, via the prescaler, or by an external clock source on
the T1 pin. The Clock Select logic block controls which clock source and edge the Timer/Counter
uses to increment (or decrement) its value. The Timer/Counter is inactive when no clock source
is selected. The output from the Clock Select logic is referred to as the timer clock (clk
The double buffered Output Compare Registers (OCR1A/B) are compared with the Timer/Coun-
ter value at all time. The result of the compare can be used by the Waveform Generator to
generate a PWM or variable frequency output on the Output Compare pin (OC1A/B). See
112. The Timer/Counter Control Registers (TCCR1A/B) are 8-bit registers and have no
1. Refer to
Timer/Counter1 pin placement and description.
Timer/Counter
Figure 1-1 on page
TCCRnA
OCRnA
OCRnB
TCNTn
ICRn
=
=
Direction
Count
Clear
2,
Table 13-3 on page 79
Control Logic
TOP
=
TCCRnB
Values
BOTTOM
Fixed
TOP
ICFn (Int.Req.)
(1)
clk
Detector
Edge
=
Tn
ATmega48P/88P/168P
0
and
”Accessing 16-bit Registers” on
OCnA
(Int.Req.)
OCnB
(Int.Req.)
TOVn
(Int.Req.)
Clock Select
Generation
Generation
Table 13-9 on page 85
( From Prescaler )
Waveform
Waveform
Canceler
Detector
Noise
Edge
Comparator Ouput )
( From Analog
OCnA
OCnB
T
ICPn
1
Tn
).
for
”Out-
111