ATMEGA649A-AU Atmel, ATMEGA649A-AU Datasheet - Page 117

IC MCU AVR 64K FLASH 64TQFP

ATMEGA649A-AU

Manufacturer Part Number
ATMEGA649A-AU
Description
IC MCU AVR 64K FLASH 64TQFP
Manufacturer
Atmel
Series
AVR® ATmegar
Datasheets

Specifications of ATMEGA649A-AU

Core Processor
AVR
Core Size
8-Bit
Speed
16MHz
Connectivity
SPI, UART/USART, USI
Peripherals
Brown-out Detect/Reset, LCD, POR, PWM, WDT
Number Of I /o
54
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)
1.8 V ~ 5.5 V
Data Converters
A/D 8x10b
Oscillator Type
Internal
Operating Temperature
-40°C ~ 85°C
Package / Case
64-TQFP
Processor Series
ATmega
Core
AVR
Data Bus Width
8 bit
Data Ram Size
4 KB
Interface Type
SPI, USART
Maximum Clock Frequency
16 MHz
Number Of Programmable I/os
54
Number Of Timers
3
Operating Supply Voltage
3.3 V
Maximum Operating Temperature
+ 85 C
Mounting Style
SMD/SMT
Minimum Operating Temperature
- 40 C
Operating Temperature Range
- 40 C to + 85 C
Lead Free Status / RoHS Status
Lead free / RoHS Compliant

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Manufacturer
Quantity
Price
Part Number:
ATMEGA649A-AU
Manufacturer:
Atmel
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Part Number:
ATMEGA649A-AUR
Manufacturer:
Atmel
Quantity:
10 000
15.3.1
15.4
8284A–AVR–10/10
Timer/Counter Clock Sources
Reusing the Temporary High Byte Register
The following code examples show how to do an atomic write of the TCNT1 Register contents.
Writing any of the OCR1A/B or ICR1 Registers can be done by using the same principle.
Note:
The assembly code example requires that the r17:r16 register pair contains the value to be writ-
ten to TCNT1.
If writing to more than one 16-bit register where the high byte is the same for all registers written,
then the high byte only needs to be written once. However, note that the same rule of atomic
operation described previously also applies in this case.
The Timer/Counter can be clocked by an internal or an external clock source. The clock source
is selected by the Clock Select logic which is controlled by the Clock Select (CS12:0) bits
located in the Timer/Counter control Register B (TCCR1B). For details on clock sources and
prescaler, see
Assembly Code Example
C Code Example
ATmega169A/169PA/329A/329PA/649A/649P/3290A/3290PA/6490A/6490P
TIM16_WriteTCNT1:
void TIM16_WriteTCNT1( unsigned int i )
{
}
; Save global interrupt flag
in r18,SREG
; Disable interrupts
cli
; Set TCNT1 to r17:r16
out TCNT1H,r17
out TCNT1L,r16
; Restore global interrupt flag
out SREG,r18
ret
unsigned char sreg;
unsigned int i;
/* Save global interrupt flag */
sreg = SREG;
/* Disable interrupts */
__disable_interrupt();
/* Set TCNT1 to i */
TCNT1 = i;
/* Restore global interrupt flag */
SREG = sreg;
1.
See ”About Code Examples” on page 11.
”Timer/Counter Timing Diagrams” on page 107
(1)
(1)
and onwards.
117

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