AT32UC3B1256 Atmel Corporation, AT32UC3B1256 Datasheet - Page 560

• Manufacturer Part Number: AT32UC3B1256
• Manufacturer: Atmel Corporation

Specifications of AT32UC3B1256

• Flash (kbytes): 256 Kbytes
• Pin Count: 48
• Max. Operating Frequency: 60 MHz
• Cpu: 32-bit AVR
• # Of Touch Channels: 32
• Hardware Qtouch Acquisition: No
• Max I/o Pins: 28
• Ext Interrupts: 28
• Usb Transceiver: 1
• Usb Speed: Full Speed
• Usb Interface: Device
• Spi: 3
• Twi (i2c): 1
• Uart: 2
• Graphic Lcd: No
• Video Decoder: No
• Camera Interface: No
• Adc Channels: 6
• Adc Resolution (bits): 10
• Adc Speed (ksps): 384
• Resistive Touch Screen: No
• Temp. Sensor: No
• Crypto Engine: No
• Sram (kbytes): 32
• Self Program Memory: YES
• Dram Memory: No
• Nand Interface: No
• Picopower: No
• Temp. Range (deg C): -40 to 85
• I/o Supply Class: 3.0-3.6 or (1.65-1.95+3.0-3.6)
• Operating Voltage (vcc): 3.0-3.6 or (1.65-1.95+3.0-3.6)
• Fpu: No
• Mpu / Mmu: Yes / No
• Timers: 10
• Output Compare Channels: 16
• Input Capture Channels: 6
• Pwm Channels: 13
• 32khz Rtc: Yes
• Calibrated Rc Oscillator: Yes

26. Audio Bitstream DAC (ABDAC)
26.1
26.2
32059L–AVR32–01/2012
Features
Overview
Rev: 1.0.1.1
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The Audio Bitstream DAC converts a 16-bit sample value to a digital bitstream with an average
value proportional to the sample value. Two channels are supported, making the Audio Bit-
stream DAC particularly suitable for stereo audio. Each channel has a pair of complementary
digital outputs, DATAn and DATANn, which can be connected to an external high input imped-
ance amplifier.
The output DATAn and DATANn should be as ideal as possible before filtering, to achieve the
best SNR and THD quality. The outputs can be connected to a class D amplifier output stage to
drive a speaker directly, or it can be low pass filtered and connected to a high input impedance
amplifier. A simple 1st order low pass filter that filters all the frequencies above 50kHz should be
adequate when applying the signal to a speaker or a bandlimited amplifier, as the speaker or
amplifier will act as a filter and remove high frequency components from the signal. In some
cases high frequency components might be folded down into the audible range, and in that case
a higher order filter is required. For performance measurements on digital equipment a minimum
of 4th order low pass filter should be used. This is to prevent aliasing in the measurements.
For the best performance when not using a class D amplifier approach, the two outputs DATAn
and DATANn, should be applied to a differential stage amplifier, as this will increase the SNR
and THD.
Digital Stereo DAC
Oversampled D/A conversion architecture
Digital bitstream outputs
Parallel interface
Connected to DMA Controller for background transfer without CPU intervention
– Oversampling ratio fixed 128x
– FIR equalization filter
– Digital interpolation filter: Comb4
– 3rd Order Sigma-Delta D/A converters
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