ATMEGA32A-PU Atmel, ATMEGA32A-PU Datasheet - Page 223

• Manufacturer Part Number: ATMEGA32A-PU
• Description: MCU AVR 32K FLASH 16MHZ 40-PDIP
• Manufacturer: Atmel
• Series: AVR® ATmegar

Specifications of ATMEGA32A-PU

• 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: 32
• Program Memory Size: 32KB (16K x 16)
• Program Memory Type: FLASH
• Eeprom Size: 1K x 8
• Ram Size: 2K 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: 40-DIP (0.600", 15.24mm)
• Processor Series: ATMEGA32x
• Core: AVR8
• Data Bus Width: 8 bit
• Data Ram Size: 2 KB
• Interface Type: 2-Wire, SPI, USART
• Maximum Clock Frequency: 16 MHz
• Number Of Programmable I/os: 32
• Number Of Timers: 3
• Maximum Operating Temperature: + 85 C
• Mounting Style: Through Hole
• 3rd Party Development Tools: EWAVR, EWAVR-BL
• Development Tools By Supplier: ATAVRDRAGON, ATSTK500, ATSTK600, ATAVRISP2, ATAVRONEKIT
• Minimum Operating Temperature: - 40 C
• On-chip Adc: 10 bit, 8 Channel
• Package: 40PDIP
• Device Core: AVR
• Family Name: ATmega
• Maximum Speed: 16 MHz
• Operating Supply Voltage: 3.3|5 V
• Data Rom Size: 1024 B
• Height: 4.83 mm
• Length: 52.58 mm
• Supply Voltage (max): 5.5 V
• Supply Voltage (min): 2.7 V
• Width: 13.97 mm
• Controller Family/series: AVR MEGA
• No. Of I/o's: 32
• Eeprom Memory Size: 1KB
• Ram Memory Size: 2KB
• Cpu Speed: 16MHz
• Rohs Compliant: Yes
• For Use With: ATSTK524 - KIT STARTER ATMEGA32M1/MEGA32C1ATSTK600 - DEV KIT FOR AVR/AVR32ATAVRDRAGON - KIT DRAGON 32KB FLASH MEM AVRATSTK500 - PROGRAMMER AVR STARTER KIT
• Lead Free Status / RoHS Status: Lead free / RoHS Compliant

22.9
22.9.1
8155C–AVR–02/11
Register Description
ADMUX – ADC Multiplexer Selection Register
Table 22-2.
Example:
• 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 22-3.
Bit
Read/Write
Initial Value
V
V
V
:.
V
V
V
:.
V
V
V
REFS1
ADCn
ADCm
ADCm
ADCm
ADCm
ADCm
ADCm
ADCm
ADCm
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.
0
0
1
1
+ 511/512 V
+ 510/512 V
+ 1/512 V
- 1/512 V
- 511/512 V
- V
+ V
REF
REF
REFS0
/GAIN
/GAIN
Correlation between Input Voltage and Output Codes
Voltage Reference Selections for ADC
0
1
0
1
REFS1
REF
REF
R/W
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
Read code
0x1FF
0x1FF
0x1FE
:.
0x001
0x000
0x3FF
:.
0x201
0x200
5
0
MUX4
R/W
4
0
Corresponding Decimal Value
511
511
510
:.
1
0
-1
:.
-511
-512
MUX3
R/W
3
0
MUX2
R/W
2
0
Table
MUX1
R/W
1
0
ATmega32A
22-3. If these bits are
MUX0
R/W
0
0
ADMUX
223