ATmega128A Atmel Corporation, ATmega128A Datasheet - Page 244

• Manufacturer Part Number: ATmega128A
• 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

8151H–AVR–02/11
where V
Table 23-3 on page 245
represents the selected reference voltage minus one LSB.
If differential channels are used, the result is
where V
GAIN the selected gain factor, and V
in two’s complement form, from 0x200 (-512d) through 0x1FF (+511d). Note that if the user
wants to perform a quick polarity check of the results, it is sufficient to read the MSB of the result
(ADC9 in ADCH). If this bit is one, the result is negative, and if this bit is zero, the result is posi-
tive.
Table 23-2
is selected with a gain of GAIN and a reference voltage of V
Figure 23-12. Differential Measurement Range
Figure 23-12
- V
REF
IN
POS
/GAIN
is the voltage on the selected input pin and V
shows the resulting output codes if the differential input channel pair (ADCn - ADCm)
is the voltage on the positive input pin, V
shows the decoding of the differential input range.
and
ADC
Table 23-4 on page
=
Output Code
(
----------------------------------------------------------------------- -
0x3FF
V
ADC
REF
POS
0x1FF
0x000
the selected voltage reference. The result is presented
–
0
=
V
0x200
NEG
V
--------------------------
V
IN
REF
V
) GAIN 512
⋅
REF
⋅
1024
246). 0x000 represents ground, and 0x3FF
NEG
REF
⋅
the voltage on the negative input pin,
REF
the selected voltage reference (see
.
ATmega128A
V
REF
/GAIN Differential Input
Voltage (Volts)
244