ATmega128A Atmel Corporation, ATmega128A Datasheet - Page 245
ATmega128A
Manufacturer Part Number
ATmega128A
Description
Manufacturer
Atmel Corporation
Specifications of ATmega128A
Flash (kbytes)
128 Kbytes
Pin Count
64
Max. Operating Frequency
16 MHz
Cpu
8-bit AVR
# Of Touch Channels
16
Hardware Qtouch Acquisition
No
Max I/o Pins
53
Ext Interrupts
8
Usb Speed
No
Usb Interface
No
Spi
1
Twi (i2c)
1
Uart
2
Graphic Lcd
No
Video Decoder
No
Camera Interface
No
Adc Channels
8
Adc Resolution (bits)
10
Adc Speed (ksps)
15
Analog Comparators
1
Resistive Touch Screen
No
Temp. Sensor
No
Crypto Engine
No
Sram (kbytes)
4
Eeprom (bytes)
4096
Self Program Memory
YES
Dram Memory
No
Nand Interface
No
Picopower
No
Temp. Range (deg C)
-40 to 85
I/o Supply Class
2.7 to 5.5
Operating Voltage (vcc)
2.7 to 5.5
Fpu
No
Mpu / Mmu
no / no
Timers
4
Output Compare Channels
8
Input Capture Channels
2
Pwm Channels
7
32khz Rtc
Yes
Calibrated Rc Oscillator
Yes
Available stocks
Company
Part Number
Manufacturer
Quantity
Price
Company:
Part Number:
ATmega128A XC6SLXFGG484CTV BCM7366ZBK W2SG0008I-T
Manufacturer:
XILINX
0
Company:
Part Number:
ATmega128A-16AU
Manufacturer:
ATMEL
Quantity:
6
Part Number:
ATmega128A-16AU
Manufacturer:
ATMEL/爱特梅尔
Quantity:
20 000
Company:
Part Number:
ATmega128A-AU
Manufacturer:
ATMEL
Quantity:
9 000
Company:
Part Number:
ATmega128A-AU
Manufacturer:
ATMEL
Quantity:
3 480
Part Number:
ATmega128A-AU
Manufacturer:
ATMEL/爱特梅尔
Quantity:
20 000
Company:
Part Number:
ATmega128A-AUR
Manufacturer:
ATMEL
Quantity:
3 000
Part Number:
ATmega128A-AUR
Manufacturer:
ATMEL/爱特梅尔
Quantity:
20 000
23.9
23.9.1
8151H–AVR–02/11
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
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
+ 511/512 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
5
0
Read code
0x1FF
0x1FF
0x1FE
0x3FF
0x001
0x000
0x201
0x200
MUX4
R/W
4
0
:.
:.
MUX3
R/W
3
0
Corresponding decimal value
511
511
510
:.
1
0
-1
:.
-511
-512
MUX2
R/W
2
0
Table
MUX1
ATmega128A
R/W
1
0
23-3. If these bits are
MUX0
R/W
0
0
ADMUX
245