Rainbow-electronics ATmega32L Manual do Utilizador descarregar pdf (Página 199)

199

ATmega32(L)

2503C–AVR–10/02

Analog to Digital

Converter

Features • 10-bit Resolution

• 0.5 LSB Integral Non-linearity

• ±2 LSB Absolute Accuracy

• 65 - 260 µs Conversion Time

• Up to 15 kSPS at Maximum Resolution

• 8 Multiplexed Single Ended Input Channels

• 7 Differential Input Channels

• 2 Differential Input Channels with Optional Gain of 10x and 200x

(1)

• Optional Left adjustment for ADC Result Readout

• 0 - V

ADC Input Voltage Range

• Selectable 2.56V 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

Note: 1. The differential input channels are not tested for devices in PDIP Package. This fea-

ture is only guaranteed to work for devices in TQFP and MLF Packages

The ATmega32 features a 10-bit successive approximation ADC. The ADC is con-

nected to an 8-channel Analog Multiplexer which allows 8 single-ended voltage inputs

constructed from the pins of Port A. The single-ended voltage inputs refer to 0V (GND).

The device also supports 16 differential voltage input combinations. Two of the differen-

tial inputs (ADC1, ADC0 and ADC3, ADC2) are equipped with a programmable gain

stage, providing amplification steps of 0 dB (1x), 20 dB (10x), or 46 dB (200x) on the dif-

ferential input voltage before the A/D conversion. Seven differential analog input

channels share a common negative terminal (ADC1), while any other ADC input can be

selected as the positive input terminal. If 1x or 10x gain is used, 8-bit resolution can be

expected. If 200x gain is used, 7-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 Figure 98.

The ADC has a separate analog supply voltage pin, AVCC. AVCC must not differ more

than ±0.3 V from V

. See the paragraph “ADC Noise Canceler” on page 207 on how to

connect this pin.

Internal reference voltages of nominally 2.56V or AVCC are provided On-chip. The volt-

age reference may be externally decoupled at the AREF pin by a capacitor for better

noise performance.

1 2 ... 194 195 196 197 198 199 200 201 202 203 204 ... 312 313

Comentários a estes Manuais

Sem comentários

Rainbow-electronics ATmega32L Manual do Utilizador Página 199

Comentários a estes Manuais

Manuais e produtos relacionados com Sensores Rainbow-electronics ATmega32L