ATMEGA32U4-MU Atmel, ATMEGA32U4-MU Datasheet - Page 6

• Manufacturer Part Number: ATMEGA32U4-MU
• Description: MCU AVR 32K FLASH 16MHZ 44-QFN
• Manufacturer: Atmel
• Series: AVR® ATmegar

Specifications of ATMEGA32U4-MU

• Core Processor: AVR
• Core Size: 8-Bit
• Speed: 16MHz
• Connectivity: I²C, SPI, UART/USART, USB
• Peripherals: Brown-out Detect/Reset, POR, PWM, WDT
• Number Of I /o: 26
• Program Memory Size: 32KB (16K x 16)
• Program Memory Type: FLASH
• Eeprom Size: 1K x 8
• Ram Size: 2.5K x 8
• Voltage - Supply (vcc/vdd): 2.7 V ~ 5.5 V
• Data Converters: A/D 12x10b
• Oscillator Type: External
• Operating Temperature: -40°C ~ 85°C
• Package / Case: 44-VQFN
• Package: 44QFN EP
• Device Core: AVR
• Family Name: ATmega
• Maximum Speed: 16 MHz
• Operating Supply Voltage: 3.3|5 V
• Data Bus Width: 8 Bit
• Number Of Programmable I/os: 26
• Interface Type: EBI/I2S/SPI/TWI/USART/USB
• On-chip Adc: 12-chx10-bit
• Number Of Timers: 5
• For Use With: ATSTK524 - KIT STARTER ATMEGA32M1/MEGA32C1ATSTK600 - DEV KIT FOR AVR/AVR32ATAVRDRAGON - KIT DRAGON 32KB FLASH MEM AVRATSTK500 - PROGRAMMER AVR STARTER KIT
• Lead Free Status / RoHS Status: Lead free / RoHS Compliant
• Other names: ATMEGA32U4-16MU; ATMEGA32U4-16MU

6.1
6.2
6.3
6
USB
Speaker
USB
Microphone
audio_task.c
evk_527.c.
usb_specific_request.c
AVR298
OUT endpoint
This file contains :
Speaker
The main audio task gets the audio samples from endpoint OUT and put it in the RAM buffer.
The OSC value tolerance doesn't allow to have an exact 32KHz frequency for the speaker, so
the main loop adjusts the timer 1 interrupt to avoid losing a sample or underrun.
Timer 1 interrupt transfers the audio data from RAM to PWM (high speed timer). Timer 1 is
responsible for adjusting data flow with PWM bits resolution and volume requested by USB host.
Note:
Microphone
Timer 0 interrupt is used to get the ADC value each 125µs (8KHz) and if the “endpoint IN” is
requested by the USB host, the value is put in this endpoint.
Figure 6-2.
This file contains all the routines to manage the EVK527 board ressources (Joystick, LEDs...).
The user should not modify this file when using the EVK527 board. Otherwise, he has to build
his own hadware management file.
This file contains the routine which receives the audio control requests, like volume level and
mute control.
• timers initialization
• timers interrupts
• routines which collect and put audio data
IN endpoint
We use only 9 bits out of the 10 bits from PWM to avoid saturation of Operational Amplifier.
Application data exchange
Audio task
Interrupt
Timer 0
RAM buffer
ADC
Interrupt
Timer 1
timer high speed
PWM
7820A–AVR–11/08