ATMEGA649V-8AI Atmel, ATMEGA649V-8AI Datasheet - Page 113
![IC AVR MCU FLASH 64K 1.8V 64TQFP](/photos/12/13/121332/313-64-tqfp_sml.jpg)
ATMEGA649V-8AI
Manufacturer Part Number
ATMEGA649V-8AI
Description
IC AVR MCU FLASH 64K 1.8V 64TQFP
Manufacturer
Atmel
Series
AVR® ATmegar
Datasheet
1.ATMEGA329-16AU.pdf
(392 pages)
Specifications of ATMEGA649V-8AI
Core Processor
AVR
Core Size
8-Bit
Speed
8MHz
Connectivity
SPI, UART/USART, USI
Peripherals
Brown-out Detect/Reset, LCD, 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)
1.8 V ~ 5.5 V
Data Converters
A/D 8x10b
Oscillator Type
Internal
Operating Temperature
-40°C ~ 85°C
Package / Case
64-TQFP, 64-VQFP
Lead Free Status / RoHS Status
Contains lead / RoHS non-compliant
Available stocks
Company
Part Number
Manufacturer
Quantity
Price
- Current page: 113 of 392
- Download datasheet (7Mb)
16.3
2552K–AVR–04/11
Accessing 16-bit Registers
The TCNT1, OCR1A/B, and ICR1 are 16-bit registers that can be accessed by the AVR CPU via
the 8-bit data bus. The 16-bit register must be byte accessed using two read or write operations.
Each 16-bit timer has a single 8-bit register for temporary storing of the high byte of the 16-bit
access. The same temporary register is shared between all 16-bit registers within each 16-bit
timer. Accessing the low byte triggers the 16-bit read or write operation. When the low byte of a
16-bit register is written by the CPU, the high byte stored in the temporary register, and the low
byte written are both copied into the 16-bit register in the same clock cycle. When the low byte of
a 16-bit register is read by the CPU, the high byte of the 16-bit register is copied into the tempo-
rary register in the same clock cycle as the low byte is read.
Not all 16-bit accesses uses the temporary register for the high byte. Reading the OCR1A/B 16-
bit registers does not involve using the temporary register.
To do a 16-bit write, the high byte must be written before the low byte. For a 16-bit read, the low
byte must be read before the high byte.
The following code examples show how to access the 16-bit Timer Registers assuming that no
interrupts updates the temporary register. The same principle can be used directly for accessing
the OCR1A/B and ICR1 Registers. Note that when using “C”, the compiler handles the 16-bit
access.
Note:
The assembly code example returns the TCNT1 value in the r17:r16 register pair.
It is important to notice that accessing 16-bit registers are atomic operations. If an interrupt
occurs between the two instructions accessing the 16-bit register, and the interrupt code
updates the temporary register by accessing the same or any other of the 16-bit Timer Regis-
ters, then the result of the access outside the interrupt will be corrupted. Therefore, when both
Assembly Code Examples
C Code Examples
...
; Set TCNT1 to 0x01FF
ldi r17,0x01
ldi r16,0xFF
out TCNT1H,r17
out TCNT1L,r16
; Read TCNT1 into r17:r16
in r16,TCNT1L
in r17,TCNT1H
...
unsigned int i;
...
/* Set TCNT1 to 0x01FF */
TCNT1 = 0x1FF;
/* Read TCNT1 into i */
i = TCNT1;
...
1.
See “About Code Examples” on page 9.
(1)
(1)
ATmega329/3290/649/6490
113
Related parts for ATMEGA649V-8AI
Image
Part Number
Description
Manufacturer
Datasheet
Request
R
![ATmega649](/images/manufacturer_photos/0/0/79/atmel_corporation_tmb.jpg)
Part Number:
Description:
Manufacturer:
Atmel Corporation
Datasheet:
![ATMEGA649-16MU](/photos/12/13/121326/313-64-qfn_tmb.jpg)
Part Number:
Description:
IC AVR MCU FLASH 64K 64-QFN
Manufacturer:
Atmel
Datasheet:
![ATMEGA649-16AU](/photos/12/13/121332/313-64-tqfp_tmb.jpg)
Part Number:
Description:
IC AVR MCU FLASH 64K 64TQFP
Manufacturer:
Atmel
Datasheet:
![ATMEGA649-16AI](/photos/12/13/121332/313-64-tqfp_tmb.jpg)
Part Number:
Description:
IC AVR MCU FLASH 64K 5V 64TQFP
Manufacturer:
Atmel
Datasheet:
![ATMEGA649-16MI](/photos/12/13/121326/313-64-qfn_tmb.jpg)
Part Number:
Description:
IC AVR MCU FLASH 64K 5V 64QFN
Manufacturer:
Atmel
Datasheet:
![ATMEGA649-16MUR](/photos/12/13/121326/313-64-qfn_tmb.jpg)
Part Number:
Description:
MCU AVR 64KB FLASH 16MHZ 64QFN
Manufacturer:
Atmel
Datasheet:
![ATMEGA649-16AUR](/photos/12/13/121332/313-64-tqfp_tmb.jpg)
Part Number:
Description:
IC MCU AVR FLASH 64K 64TQFP
Manufacturer:
Atmel
Datasheet:
![ATmega64](/images/manufacturer_photos/0/0/79/atmel_corporation_tmb.jpg)
Part Number:
Description:
Manufacturer:
Atmel Corporation
Datasheet:
![ATMEGA64-16 AU](/images/manufacturer_photos/0/0/79/atmel_corporation_tmb.jpg)
Part Number:
Description:
Manufacturer:
ATMEL Corporation
Datasheet:
![ATMEGA64-16 AC](/images/manufacturer_photos/0/0/79/atmel_corporation_tmb.jpg)
Part Number:
Description:
Manufacturer:
ATMEL Corporation
Datasheet:
![ATMEGA64-16AU](/photos/12/13/121332/313-64-tqfp_tmb.jpg)
Part Number:
Description:
IC AVR MCU 64K 16MHZ 5V 64TQFP
Manufacturer:
Atmel
Datasheet:
![ATMEGA64-16MU](/photos/12/13/121326/313-64-qfn_tmb.jpg)
Part Number:
Description:
IC AVR MCU 64K 16MHZ 5V 64-QFN
Manufacturer:
Atmel
Datasheet:
![ATMEGA64-16AC](/photos/12/13/121332/313-64-tqfp_tmb.jpg)
Part Number:
Description:
IC AVR MCU 64K 16MHZ COM 64-TQFP
Manufacturer:
Atmel
Datasheet:
![ATMEGA64-16AI](/photos/12/13/121332/313-64-tqfp_tmb.jpg)
Part Number:
Description:
IC AVR MCU 64K 16MHZ IND 64-TQFP
Manufacturer:
Atmel
Datasheet:
![ATMEGA64-16MC](/images/manufacturer_photos/0/0/78/atmel_tmb.jpg)
Part Number:
Description:
IC AVR MCU 64K 16MHZ COM 64-QFN
Manufacturer:
Atmel
Datasheet: