ATMEGA644A-MU Atmel, ATMEGA644A-MU Datasheet - Page 109
![IC MCU AVR 64K FLASH 44VQFN](/photos/12/13/121316/313-44-qfn_sml.jpg)
ATMEGA644A-MU
Manufacturer Part Number
ATMEGA644A-MU
Description
IC MCU AVR 64K FLASH 44VQFN
Manufacturer
Atmel
Series
AVR® ATmegar
Specifications of ATMEGA644A-MU
Core Processor
AVR
Core Size
8-Bit
Speed
20MHz
Connectivity
I²C, SPI, UART/USART
Peripherals
Brown-out Detect/Reset, POR, PWM, WDT
Number Of I /o
32
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
44-VQFN Exposed Pad
Lead Free Status / RoHS Status
Lead free / RoHS Compliant
- Current page: 109 of 581
- Download datasheet (27Mb)
14.9.3
14.9.4
8272A–AVR–01/10
TCNT0 – Timer/Counter Register
OCR0A – Output Compare Register A
• Bits 2:0 – CS02:0: Clock Select
The three Clock Select bits select the clock source to be used by the Timer/Counter.
Table 14-9.
If external pin modes are used for the Timer/Counter0, transitions on the T0 pin will clock the
counter even if the pin is configured as an output. This feature allows software control of the
counting.
The Timer/Counter Register gives direct access, both for read and write operations, to the
Timer/Counter unit 8-bit counter. Writing to the TCNT0 Register blocks (removes) the Compare
Match on the following timer clock. Modifying the counter (TCNT0) while the counter is running,
introduces a risk of missing a Compare Match between TCNT0 and the OCR0x Registers.
The Output Compare Register A contains an 8-bit value that is continuously compared with the
counter value (TCNT0). A match can be used to generate an Output Compare interrupt, or to
generate a waveform output on the OC0A pin.
164A/164PA/324A/324PA/644A/644PA/1284/1284P
Bit
0x26 (0x46)
Read/Write
Initial Value
Bit
0x27 (0x47)
Read/Write
Initial Value
CS02
0
0
0
0
1
1
1
1
CS01
0
0
1
1
0
0
1
1
Clock Select Bit Description
R/W
R/W
7
0
7
0
CS00
0
1
0
1
0
1
0
1
R/W
R/W
6
0
6
0
Description
No clock source (Timer/Counter stopped)
clk
clk
clk
clk
clk
External clock source on T0 pin. Clock on falling edge.
External clock source on T0 pin. Clock on rising edge.
I/O
I/O
I/O
I/O
I/O
/(No prescaling)
/8 (From prescaler)
/64 (From prescaler)
/256 (From prescaler)
/1024 (From prescaler)
R/W
R/W
5
0
5
0
R/W
R/W
4
0
4
0
OCR0A[7:0]
TCNT0[7:0]
R/W
R/W
3
0
3
0
R/W
R/W
2
0
2
0
R/W
R/W
1
0
1
0
R/W
R/W
0
0
0
0
OCR0A
TCNT0
109
Related parts for ATMEGA644A-MU
Image
Part Number
Description
Manufacturer
Datasheet
Request
R
![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:
![ATMEGA64-16AUR](/photos/12/13/121332/313-64-tqfp_tmb.jpg)
Part Number:
Description:
MCU AVR 64KB FLASH 16MHZ 64TQFP
Manufacturer:
Atmel
Datasheet:
![ATMEGA64-16MUR](/images/manufacturer_photos/0/0/78/atmel_tmb.jpg)
Part Number:
Description:
MCU AVR 64KB FLASH 16MHZ 64QFN
Manufacturer:
Atmel
Datasheet:
![ATMEGA64-16MI](/images/manufacturer_photos/0/0/78/atmel_tmb.jpg)
Part Number:
Description:
IC AVR MCU 64K 16MHZ IND 64-QFN
Manufacturer:
Atmel
Datasheet:
![ATMEGA64-16AJ](/photos/12/13/121332/313-64-tqfp_tmb.jpg)
Part Number:
Description:
IC MCU AVR 64K 5V 16MHZ 64-TQFP
Manufacturer:
Atmel
Datasheet:
![ATMEGA64-16MJ](/images/manufacturer_photos/0/0/78/atmel_tmb.jpg)
Part Number:
Description:
IC MCU AVR 64K 5V 16MHZ 64-QFN
Manufacturer:
Atmel
Datasheet:
![ATMEGA64-16AU SL383](/images/manufacturer_photos/0/0/78/atmel_tmb.jpg)
Part Number:
Description:
MCU 8-Bit ATmega AVR RISC 64KB Flash 5V 64-Pin TQFP T/R
Manufacturer:
Atmel
Datasheet: