ATMEGA8A-PU Atmel, ATMEGA8A-PU Datasheet - Page 114

MCU AVR 8K FLASH 16MHZ 28-PDIP

ATMEGA8A-PU

Manufacturer Part Number
ATMEGA8A-PU
Description
MCU AVR 8K FLASH 16MHZ 28-PDIP
Manufacturer
Atmel
Series
AVR® ATmegar
Datasheets

Specifications of ATMEGA8A-PU

Core Processor
AVR
Core Size
8-Bit
Speed
16MHz
Connectivity
I²C, SPI, UART/USART
Peripherals
Brown-out Detect/Reset, POR, PWM, WDT
Number Of I /o
23
Program Memory Size
8KB (4K x 16)
Program Memory Type
FLASH
Eeprom Size
512 x 8
Ram Size
1K 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)
Processor Series
ATMEGA8x
Core
AVR8
Data Bus Width
8 bit
Data Ram Size
1 KB
Interface Type
SPI, TWI, USART
Maximum Clock Frequency
16 MHz
Number Of Programmable I/os
23
Number Of Timers
3
Maximum Operating Temperature
+ 85 C
Mounting Style
Through Hole
3rd Party Development Tools
EWAVR, EWAVR-BL
Development Tools By Supplier
ATAVRDRAGON, ATSTK500, ATSTK600, ATAVRISP2, ATAVRONEKIT
Minimum Operating Temperature
- 40 C
On-chip Adc
10 bit, 6 Channel
Package
28PDIP
Device Core
AVR
Family Name
ATmega
Maximum Speed
16 MHz
Operating Supply Voltage
3.3|5 V
Controller Family/series
AVR MEGA
No. Of I/o's
23
Eeprom Memory Size
512Byte
Ram Memory Size
1KB
Cpu Speed
16MHz
Rohs Compliant
Yes
For Use With
ATSTK600 - DEV KIT FOR AVR/AVR32ATSTK500 - PROGRAMMER AVR STARTER KIT
Lead Free Status / RoHS Status
Lead free / RoHS Compliant

Available stocks

Company
Part Number
Manufacturer
Quantity
Price
Part Number:
ATMEGA8A-PU
Manufacturer:
ATMEL/爱特梅尔
Quantity:
20 000
8159D–AVR–02/11
operating frequency of the fast PWM mode can be twice as high as the phase correct PWM
mode that uses dual-slope operation. This high frequency makes the fast PWM mode well suited
for power regulation, rectification, and DAC applications. High frequency allows physically small
sized external components (coils, capacitors), and therefore reduces total system cost.
In fast PWM mode, the counter is incremented until the counter value matches the MAX value.
The counter is then cleared at the following timer clock cycle. The timing diagram for the fast
PWM mode is shown in
togram for illustrating the single-slope operation. The diagram includes non-inverted and
inverted PWM outputs. The small horizontal line marks on the TCNT2 slopes represent compare
matches between OCR2 and TCNT2.
Figure 17-6. Fast PWM Mode, Timing Diagram
The Timer/Counter Overflow Flag (TOV2) is set each time the counter reaches MAX. If the inter-
rupt is enabled, the interrupt handler routine can be used for updating the compare value.
In fast PWM mode, the compare unit allows generation of PWM waveforms on the OC2 pin. Set-
ting the COM21:0 bits to 2 will produce a non-inverted PWM and an inverted PWM output can
be generated by setting the COM21:0 to 3 (see
will only be visible on the port pin if the data direction for the port pin is set as output. The PWM
waveform is generated by setting (or clearing) the OC2 Register at the Compare Match between
OCR2 and TCNT2, and clearing (or setting) the OC2 Register at the timer clock cycle the coun-
ter is cleared (changes from MAX to BOTTOM).
The PWM frequency for the output can be calculated by the following equation:
The N variable represents the prescale factor (1, 8, 32, 64, 128, 256, or 1024).
The extreme values for the OCR2 Register represent special cases when generating a PWM
waveform output in the fast PWM mode. If the OCR2 is set equal to BOTTOM, the output will be
TCNTn
OCn
OCn
Period
1
Figure
2
17-6. The TCNT2 value is in the timing diagram shown as a his-
3
f
OCnPWM
4
Table 17-4 on page
=
----------------- -
N 256
f
clk_I/O
5
6
122). The actual OC2 value
OCRn Interrupt Flag Set
OCRn Update
and
TOVn Interrupt Flag Set
7
ATmega8A
(COMn1:0 = 2)
(COMn1:0 = 3)
114

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