Analog To Digital Converter - Adc; Features - Atmel ATmega32M1 Manual

18. Analog to Digital Converter - ADC

18.1

Features

Atmel ATmega16/32/64/M1/C1
230
•
10-bit Resolution
•
0.8 LSB Integral Non-linearity (at 2 Mhz)
•
±3.2 LSB Absolute Accuracy
•
8- 250 µs Conversion Time
•
Up to 125 kSPS at Maximum Resolution
•
11 Multiplexed Single Ended Input Channels
•
3 Differential input channels with programmable gain 5, 10, 20 and 40
•
Optional Left Adjustment for ADC Result Readout
•
0 - V ADC Input Voltage Range
CC
•
Selectable 2.56 V ADC Reference Voltage
•
Free Running or Single Conversion Mode
•
ADC Start Conversion by Auto Triggering on Interrupt Sources
•
Interrupt on ADC Conversion Complete
•
Sleep Mode Noise Canceler
•
Temperature Sensor
•
LiN Address Sense (ISRC Voltage Measurement)
•
Vcc Voltage Measurement
The ATmega16/32/64/M1/C1 features a 10-bit successive approximation ADC. The ADC is con-
nected to an 15-channel Analog Multiplexer which allows eleven single-ended input. The
single-ended voltage inputs refer to 0V (GND).
The device also supports 3 differential voltage input amplifiers which are equipped with a pro-
grammable gain stage, providing amplification steps of 14dB (5x), 20 dB (10x), 26 dB (20x), or
32dB (40x) on the differential input voltage before the A/D conversion. On the amplified chan-
nels, 8-bit resolution can be expected.
The ADC contains a Sample and Hold circuit which ensures that the input voltage to the ADC is
held at a constant level during conversion. A block diagram of the ADC is shown in
The ADC has a separate analog supply voltage pin, AV
from V . See the paragraph
CC
Internal reference voltages of nominally 2.56V or AV
ence may be externally decoupled at the AREF pin by a capacitor (e.g., 10 nF) for better noise
performance. In any case this capacitor shout not be greater than 10% of the AVCC smoothing
capacitor.
"ADC Noise Canceler" on page 237
CC
. AV must not differ more than ±0.3V
CC CC
on how to connect this pin.
are provided On-chip. The voltage refer-
Figure 18-1.
7647H–AVR–03/12