ATMEGA649V-8AI Atmel, ATMEGA649V-8AI Datasheet - Page 209

• Manufacturer Part Number: ATMEGA649V-8AI
• Description: IC AVR MCU FLASH 64K 1.8V 64TQFP
• Manufacturer: Atmel
• Series: AVR® ATmegar

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

21.3
21.3.1
21.3.2
2552K–AVR–04/11
Register Description
ADCSRB – ADC Control and Status Register B
ACSR – Analog Comparator Control and Status Register
• Bit 6 – ACME: Analog Comparator Multiplexer Enable
When this bit is written logic one and the ADC is switched off (ADEN in ADCSRA is zero), the
ADC multiplexer selects the negative input to the Analog Comparator. When this bit is written
logic zero, AIN1 is applied to the negative input of the Analog Comparator. For a detailed
description of this bit, see
• Bit 7 – ACD: Analog Comparator Disable
When this bit is written logic one, the power to the Analog Comparator is switched off. This bit
can be set at any time to turn off the Analog Comparator. This will reduce power consumption in
Active and Idle mode. When changing the ACD bit, the Analog Comparator Interrupt must be
disabled by clearing the ACIE bit in ACSR. Otherwise an interrupt can occur when the bit is
changed.
• Bit 6 – ACBG: Analog Comparator Bandgap Select
When this bit is set, a fixed bandgap reference voltage replaces the positive input to the Analog
Comparator. When this bit is cleared, AIN0 is applied to the positive input of the Analog Compar-
ator. When the bandgap reference is used as input to the analog comparator, it will take a
certain time for the voltage to stabilize. If not stabilized, the the first converison may give a wrong
value.
• Bit 5 – ACO: Analog Comparator Output
The output of the Analog Comparator is synchronized and then directly connected to ACO. The
synchronization introduces a delay of 1 - 2 clock cycles.
• Bit 4 – ACI: Analog Comparator Interrupt Flag
This bit is set by hardware when a comparator output event triggers the interrupt mode defined
by ACIS1 and ACIS0. The Analog Comparator interrupt routine is executed if the ACIE bit is set
and the I-bit in SREG is set. ACI is cleared by hardware when executing the corresponding inter-
rupt handling vector. Alternatively, ACI is cleared by writing a logic one to the flag.
Bit
(0x7B)
Read/Write
Initial Value
Bit
0x30 (0x50)
Read/Write
Initial Value
See “Internal Voltage Reference” on page 44.
ACD
R/W
R
7
0
7
–
0
ACBG
ACME
R/W
R/W
6
0
6
0
“Analog Comparator Multiplexed Input” on page
ACO
N/A
R
5
R
5
–
0
R/W
ACI
4
0
R
4
–
0
ATmega329/3290/649/6490
ACIE
R/W
3
0
R
3
–
0
ADTS2
ACIC
R/W
R/W
2
0
2
0
ACIS1
ADTS1
R/W
R/W
1
0
1
0
ACIS0
ADTS0
R/W
R/W
0
0
0
0
208.
ADCSRB
ACSR
209