ATMEGA64A-MNR Atmel, ATMEGA64A-MNR Datasheet - Page 247

• 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

23.9
23.9.1
8160C–AVR–07/09
Register Description
ADMUX – ADC Multiplexer Selection Register
Table 23-2.
Example:
ADMUX = 0xED (ADC3 - ADC2, 10x gain, 2.56V reference, left adjusted result).
Voltage on ADC3 is 300 mV, voltage on ADC2 is 500 mV.
ADCR = 512 * 10 * (300 - 500) / 2560 = -400 = 0x270.
ADCL will thus read 0x00, and ADCH will read 0x9C. Writing zero to ADLAR right adjusts the
result: ADCL = 0x70, ADCH = 0x02.
• Bit 7:6 – REFS1:0: Reference Selection Bits
These bits select the voltage reference for the ADC, as shown in
changed during a conversion, the change will not go in effect until this conversion is complete
(ADIF in ADCSRA is set). The internal voltage reference options may not be used if an external
reference voltage is being applied to the AREF pin.
Table 23-3.
Bit
0x07 (0x27)
Read/Write
Initial Value
V
V
V
:.
V
V
V
:.
V
V
V
REFS1
ADCn
ADCm
ADCm
ADCm
ADCm
ADCm
ADCm
ADCm
ADCm
0
0
1
1
+ 511/512 V
+ 510/512 V
+ 1/512 V
- 1/512 V
- 511/512V
- V
+ V
REF
REF
REFS0
/GAIN
/GAIN
REFS1
Correlation Between Input Voltage and Output Codes
Voltage Reference Selections for ADC
R/W
0
1
0
1
REF
REF
7
0
REF
REF
REF
/GAIN
/GAIN
/GAIN
/GAIN
/GAIN
Voltage Reference Selection
AREF, Internal Vref turned off.
AVCC with external capacitor at AREF pin.
Reserved
Internal 2.56V Voltage Reference with external capacitor at AREF pin.
REFS0
R/W
6
0
ADLAR
R/W
5
0
Read Code
0x1FF
0x1FF
0x1FE
:.
0x001
0x000
0x3FF
:.
0x201
0x200
MUX4
R/W
4
0
MUX3
R/W
3
0
MUX2
Corresponding Decimal Value
R/W
2
0
Table
MUX1
R/W
1
0
ATmega64A
-511
-512
511
511
510
23-3. If these bits are
-1
:.
1
0
:.
MUX0
R/W
0
0
ADMUX
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