ATMEGA64A-MNR Atmel, ATMEGA64A-MNR Datasheet - Page 108

• Manufacturer Part Number: ATMEGA64A-MNR
• Description: IC MCU AVR 64K FLASH 8QFN
• Manufacturer: Atmel
• Series: AVR® ATmegar

Specifications of ATMEGA64A-MNR

• 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: *
• Core: AVR8
• Data Bus Width: 8 bit
• Data Ram Size: 2 KB
• Interface Type: SPI, UART, I2C
• Maximum Clock Frequency: 16 MHz
• Number Of Programmable I/os: 53
• Operating Supply Voltage: 2.7 V to 5.5 V
• Maximum Operating Temperature: + 105 C
• Mounting Style: SMD/SMT
• Operating Temperature Range: - 40 C to + 85 C
• Processor To Be Evaluated: ATMEGA64A
• Lead Free Status / RoHS Status: Lead free / RoHS Compliant

14.11.2
14.11.3
14.11.4
8160C–AVR–07/09
TCNT0 – Timer/Counter Register
OCR0 – Output Compare Register
ASSR – Asynchronous Status Register
Table 14-6.
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 OCR0 Register.
The Output Compare Register 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 OC0 pin.
• Bit 3 – AS0: Asynchronous Timer/Counter0
When AS0 is written to zero, Timer/Counter0 is clocked from the I/O clock, clk
written to one, Timer/Counter 0 is clocked from a crystal Oscillator connected to the Timer Oscil-
lator 1 (TOSC1) pin. When the value of AS0 is changed, the contents of TCNT0, OCR0, and
TCCR0 might be corrupted.
Bit
0x32 (0x52)
Read/Write
Initial Value
Bit
0x31 (0x51)
Read/Write
Initial Value
Bit
0x30 (0x50)
Read/Write
Initial Value
CS02
0
0
0
0
1
1
1
1
Clock Select Bit Description
CS01
R/W
R/W
R
7
–
0
7
0
7
0
0
0
1
1
0
0
1
1
R
6
–
0
R/W
R/W
6
0
6
0
CS00
0
1
0
1
0
1
0
1
R
5
–
0
R/W
R/W
5
0
5
0
Description
No clock source (Timer/counter stopped)
clk
clk
clk
clk
clk
clk
clk
T0S
T0S
T0S
T0S
T0S
T
T
0
0
R
4
–
0
S
S
/256 (From prescaler)
/1024 (From prescaler)
/(No prescaling)
/8 (From prescaler)
/32 (From prescaler)
/64 (From prescaler)
/128 (From prescaler)
R/W
R/W
4
0
4
0
TCNT0[7:0]
OCR0[7:0]
AS0
R/W
3
0
R/W
R/W
3
0
3
0
TCN0UB
R
2
0
R/W
R/W
2
0
2
0
OCR0UB
R
1
0
R/W
R/W
1
0
1
0
ATmega64A
TCR0UB
R
0
0
R/W
I/O
R/W
0
0
0
0
. When AS0 is
TCNT0
ASSR
OCR0
108