ATMEGA48-20PJ Atmel, ATMEGA48-20PJ Datasheet - Page 98

• Manufacturer Part Number: ATMEGA48-20PJ
• Description: IC AVR MCU 4K 5V 20MHZ 28-DIP
• Manufacturer: Atmel
• Series: AVR® ATmegar

Specifications of ATMEGA48-20PJ

• Core Processor: AVR
• Core Size: 8-Bit
• Speed: 20MHz
• Connectivity: I²C, SPI, UART/USART
• Peripherals: Brown-out Detect/Reset, POR, PWM, WDT
• Number Of I /o: 23
• Program Memory Size: 4KB (2K x 16)
• Program Memory Type: FLASH
• Eeprom Size: 256 x 8
• Ram Size: 512 x 8
• Voltage - Supply (vcc/vdd): 2.7 V ~ 5.5 V
• Data Converters: A/D 6x10b
• Oscillator Type: Internal
• Operating Temperature: -40°C ~ 85°C
• Package / Case: 28-DIP (0.300", 7.62mm)
• Lead Free Status / RoHS Status: Lead free / RoHS Compliant
• Other names: ATMEGA48-24PJ; ATMEGA48-24PJ

14.8
98
Timer/Counter Timing Diagrams
ATmega48/88/168
• The timer starts counting from a value higher than the one in OCRnx, and for that reason
The Timer/Counter is a synchronous design and the timer clock (clk
clock enable signal in the following figures. The figures include information on when interrupt
flags are set.
shows the count sequence close to the MAX value in all modes other than phase correct PWM
mode.
Figure 14-8. Timer/Counter Timing Diagram, no Prescaling
Figure 14-9
Figure 14-9. Timer/Counter Timing Diagram, with Prescaler (f
Figure 14-10
mode and PWM mode, where OCR0A is TOP.
symmetry around BOTTOM the OCnx value at MAX must correspond to the result of an up-
counting Compare Match.
misses the Compare Match and hence the OCnx change that would have happened on the
way up.
TCNTn
TCNTn
(clk
(clk
TOVn
TOVn
clk
clk
clk
clk
I/O
I/O
I/O
I/O
Tn
Tn
/1)
/8)
shows the same timing data, but with the prescaler enabled.
shows the setting of OCF0B in all modes and OCF0A in all modes except CTC
Figure 14-8
MAX - 1
MAX - 1
contains timing data for basic Timer/Counter operation. The figure
MAX
MAX
BOTTOM
BOTTOM
clk_I/O
/8)
T0
) is therefore shown as a
BOTTOM + 1
BOTTOM + 1
2545S–AVR–07/10