ATMEGA644P-A15MZ Atmel, ATMEGA644P-A15MZ Datasheet - Page 256

• Manufacturer Part Number: ATMEGA644P-A15MZ
• Description: MCU AVR 64KB FLASH 16MHZ 44QFN
• Manufacturer: Atmel
• Series: AVR® ATmegar

Specifications of ATMEGA644P-A15MZ

• Package / Case: 44-VQFN Exposed Pad
• Voltage - Supply (vcc/vdd): 2.7 V ~ 5.5 V
• Operating Temperature: -40°C ~ 125°C
• Speed: 16MHz
• Number Of I /o: 32
• Eeprom Size: 2K x 8
• Core Processor: AVR
• Program Memory Type: FLASH
• Ram Size: 4K x 8
• Program Memory Size: 64KB (64K x 8)
• Data Converters: A/D 8x10b
• Oscillator Type: Internal
• Peripherals: Brown-out Detect/Reset, POR, PWM, WDT
• Connectivity: I²C, SPI, UART/USART
• Core Size: 8-Bit
• Lead Free Status / RoHS Status: Lead free / RoHS Compliant

21.8
256
ADC Conversion Result
ATmega164P/324P/644P
After the conversion is complete (ADIF is high), the conversion result can be found in the ADC
Result Registers (ADCL, ADCH).
For single ended conversion, the result is
where V
Table 21-3 on page 258
0x3FF 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 21-2 on page 257
(ADCn - ADCm) is selected with a gain of GAIN and a reference voltage of V
Figure 21-14 on page 257
IN
POS
is the voltage on the selected input pin and V
is the voltage on the positive input pin, V
ADC
and
shows the resulting output codes if the differential input channel pair
Table 21-4 on page
=
shows the decoding of the differential input range.
----------------------------------------------------------------------------- -
V
POS
ADC
REF
–
the selected voltage reference. The result is presented
V
=
NEG
V
---------------------------- -
V
IN
REF
V
REF
1024
GAIN
259). 0x000 represents analog ground, and
NEG
REF
the voltage on the negative input pin,
512
the selected voltage reference (see
REF
.
7674F–AVR–09/09