ATMEGA128A-AU Atmel, ATMEGA128A-AU Datasheet - Page 153
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ATMEGA128A-AU
Manufacturer Part Number
ATMEGA128A-AU
Description
MCU 8BIT 128K ISP FLASH 64-TQFP
Manufacturer
Atmel
Series
AVR® ATmegar
Specifications of ATMEGA128A-AU
Core Processor
AVR
Core Size
8-Bit
Speed
16MHz
Connectivity
EBI/EMI, I²C, SPI, UART/USART
Peripherals
Brown-out Detect/Reset, POR, PWM, WDT
Number Of I /o
53
Program Memory Size
128KB (64K x 16)
Program Memory Type
FLASH
Eeprom Size
4K x 8
Ram Size
4K x 8
Voltage - Supply (vcc/vdd)
2.7 V ~ 5.5 V
Data Converters
A/D 8x10b
Oscillator Type
Internal
Operating Temperature
-40°C ~ 85°C
Package / Case
64-TQFP, 64-VQFP
Processor Series
ATMEGA128x
Core
AVR8
Data Bus Width
8 bit
Data Ram Size
4 KB
Interface Type
JTAG
Maximum Clock Frequency
16 MHz
Number Of Programmable I/os
53
Number Of Timers
4
Operating Supply Voltage
2.7 V to 5.5 V
Maximum Operating Temperature
+ 85 C
Mounting Style
SMD/SMT
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, 8 Channel
On-chip Dac
10 bit, 8 Channel
Cpu Family
ATmega
Device Core
AVR
Device Core Size
8b
Frequency (max)
16MHz
Total Internal Ram Size
4KB
# I/os (max)
53
Number Of Timers - General Purpose
4
Operating Supply Voltage (typ)
3.3/5V
Operating Supply Voltage (max)
5.5V
Operating Supply Voltage (min)
2.7V
Instruction Set Architecture
RISC
Operating Temp Range
-40C to 85C
Operating Temperature Classification
Industrial
Mounting
Surface Mount
Pin Count
64
Package Type
TQFP
Lead Free Status / RoHS Status
Lead free / RoHS Compliant
Other names
Q4784435
Available stocks
Company
Part Number
Manufacturer
Quantity
Price
Company:
Part Number:
ATMEGA128A-AU
Manufacturer:
ATMEL
Quantity:
9 000
Company:
Part Number:
ATMEGA128A-AU
Manufacturer:
ATMEL
Quantity:
3 480
Part Number:
ATMEGA128A-AU
Manufacturer:
ATMEL/爱特梅尔
Quantity:
20 000
Company:
Part Number:
ATMEGA128A-AUR
Manufacturer:
ATMEL
Quantity:
3 000
Part Number:
ATMEGA128A-AUR
Manufacturer:
ATMEL/爱特梅尔
Quantity:
20 000
17.6.1
17.7
17.7.1
17.7.2
8151H–AVR–02/11
Modes of Operation
Compare Output Mode and Waveform Generation
Normal Mode
Clear Timer on Compare Match (CTC) Mode
The waveform generator uses the COM21:0 bits differently in normal, CTC, and PWM modes.
For all modes, setting the COM21:0 = 0 tells the waveform generator that no action on the OC2
Register is to be performed on the next compare match. For compare output actions in the non-
PWM modes refer to
160, and for phase correct PWM refer to
A change of the COM21:0 bits state will have effect at the first compare match after the bits are
written. For non-PWM modes, the action can be forced to have immediate effect by using the
FOC2 strobe bits.
The mode of operation, that is, the behavior of the Timer/Counter and the Output Compare pins,
is defined by the combination of the Waveform Generation mode (WGM21:0) and Compare Out-
put mode (COM21:0) bits. The Compare Output mode bits do not affect the counting sequence,
while the Waveform Generation mode bits do. The COM21:0 bits control whether the PWM out-
put generated should be inverted or not (inverted or non-inverted PWM). For non-PWM modes
the COM21:0 bits control whether the output should be set, cleared, or toggled at a compare
match (see “Compare Match Output Unit” on page 152).
For detailed timing information refer to
in
The simplest mode of operation is the normal mode (WGM21:0 = 0). In this mode the counting
direction is always up (incrementing), and no counter clear is performed. The counter simply
overruns when it passes its maximum 8-bit value (TOP = 0xFF) and then restarts from the bot-
tom (0x00). In normal operation the Timer/Counter overflow flag (
timer clock cycle as the TCNT2 becomes zero. The
bit, except that it is only set, not cleared. However, combined with the timer overflow interrupt
that automatically clears the
are no special cases to consider in the normal mode, a new counter value can be written
anytime.
The output compare unit can be used to generate interrupts at some given time. Using the out-
put compare to generate waveforms in normal mode is not recommended, since this will occupy
too much of the CPU time.
In Clear Timer on Compare or CTC mode (WGM21:0 = 2), the OCR2 Register is used to manip-
ulate the counter resolution. In CTC mode the counter is cleared to zero when the counter value
(TCNT2) matches the OCR2. The OCR2 defines the top value for the counter, hence also its
resolution. This mode allows greater control of the compare match output frequency. It also sim-
plifies the operation of counting external events.
The timing diagram for the CTC mode is shown in
increases until a compare match occurs between TCNT2 and OCR2 and then counter (TCNT2)
is cleared.
“Timer/Counter Timing Diagrams” on page
Table 17-3 on page
TOV
2 flag, the timer resolution can be increased by software. There
Figure
Table 17-5 on page
160. For fast PWM mode, refer to
157.
17-8,
Figure
TOV
Figure
2 flag in this case behaves like a ninth
17-9,
17-5. The counter value (TCNT2)
161.
Figure
TOV
ATmega128A
2) will be set in the same
17-10, and
Table 17-4 on page
Figure 17-11
153