ATMEGA64A-AU Atmel, ATMEGA64A-AU Datasheet - Page 119
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ATMEGA64A-AU
Manufacturer Part Number
ATMEGA64A-AU
Description
MCU AVR 64K ISP FLASH 64-TQFP
Manufacturer
Atmel
Series
AVR® ATmegar
Datasheets
1.ATMEGA64A-MUR.pdf
(21 pages)
2.ATMEGA64A-AU.pdf
(392 pages)
3.ATMEGA64A-AU.pdf
(3 pages)
Specifications of ATMEGA64A-AU
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
53
Program Memory Size
64KB (32K x 16)
Program Memory Type
FLASH
Eeprom Size
2K 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
Package
64TQFP
Device Core
AVR
Family Name
ATmega
Maximum Speed
16 MHz
Operating Supply Voltage
3.3|5 V
Data Bus Width
8 Bit
Number Of Programmable I/os
53
Interface Type
SPI/USART
On-chip Adc
8-chx10-bit
Number Of Timers
4
Processor Series
ATMEGA64x
Core
AVR8
Data Ram Size
4 KB
Maximum Clock Frequency
16 MHz
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
Cpu Family
ATmega
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
For Use With
770-1007 - ISP 4PORT ATMEL AVR MCU SPI/JTAG
Lead Free Status / RoHS Status
Lead free / RoHS Compliant
Available stocks
Company
Part Number
Manufacturer
Quantity
Price
Company:
Part Number:
ATMEGA64A-AU
Manufacturer:
ATMEL
Quantity:
4 500
Company:
Part Number:
ATMEGA64A-AU
Manufacturer:
Atmel
Quantity:
900
Company:
Part Number:
ATMEGA64A-AU
Manufacturer:
ATMEL85
Quantity:
900
Part Number:
ATMEGA64A-AU
Manufacturer:
AT
Quantity:
20 000
15.6.1
15.6.2
15.6.3
8160C–AVR–07/09
Input Capture Source
Noise Canceler
Using the Input Capture Unit
The ICRn Register can only be written when using a Waveform Generation mode that utilizes
the ICRn Register for defining the counter’s TOP value. In these cases the Waveform Genera-
tion mode (WGMn3:0) bits must be set before the TOP value can be written to the ICRn
Register. When writing the ICRn Register the high byte must be written to the ICRnH I/O location
before the low byte is written to ICRnL.
For more information on how to access the 16-bit registers refer to
on page
The main trigger source for the Input Capture unit is the Input Capture pin (ICPn).
Timer/Counter1 can alternatively use the Analog Comparator output as trigger source for the
Input Capture unit. The Analog Comparator is selected as trigger source by setting the Analog
Comparator Input Capture (ACIC) bit in the Analog Comparator Control and Status Register
(ACSR). Be aware that changing trigger source can trigger a capture. The Input Capture Flag
must therefore be cleared after the change.
Both the Input Capture pin (ICPn) and the Analog Comparator output (ACO) inputs are sampled
using the same technique as for the Tn pin
identical. However, when the noise canceler is enabled, additional logic is inserted before the
edge detector, which increases the delay by four system clock cycles. Note that the input of the
noise canceler and edge detector is always enabled unless the Timer/Counter is set in a Wave-
form Generation mode that uses ICRn to define TOP.
An Input Capture can be triggered by software by controlling the port of the ICPn pin.
The Noise Canceler improves noise immunity by using a simple digital filtering scheme. The
Noise Canceler input is monitored over four samples, and all four must be equal for changing the
output that in turn is used by the edge detector.
The Noise Canceler is enabled by setting the Input Capture Noise Canceler (ICNCn) bit in
Timer/Counter Control Register B (TCCRnB). When enabled the Noise Canceler introduces
additional four system clock cycles of delay from a change applied to the input, to the update of
the ICRn Register. The Noise Canceler uses the system clock and is therefore not affected by
the prescaler.
The main challenge when using the Input Capture unit is to assign enough processor capacity
for handling the incoming events. The time between two events is critical. If the processor has
not read the captured value in the ICRn Register before the next event occurs, the ICRn will be
overwritten with a new value. In this case the result of the capture will be incorrect.
When using the Input Capture interrupt, the ICRn Register should be read as early in the inter-
rupt handler routine as possible. Even though the Input Capture interrupt has relatively high
priority, the maximum interrupt response time is dependent on the maximum number of clock
cycles it takes to handle any of the other interrupt requests.
Using the Input Capture unit in any mode of operation when the TOP value (resolution) is
actively changed during operation, is not recommended.
Measurement of an external signal’s duty cycle requires that the trigger edge is changed after
each capture. Changing the edge sensing must be done as early as possible after the ICRn
114.
(Figure 16-1 on page
143). The edge detector is also
“Accessing 16-bit Registers”
ATmega64A
119