ATmega32U4 Atmel Corporation, ATmega32U4 Datasheet - Page 428

• Manufacturer Part Number: ATmega32U4
• Manufacturer: Atmel Corporation

Specifications of ATmega32U4

• Flash (kbytes): 32 Kbytes
• Pin Count: 44
• Max. Operating Frequency: 16 MHz
• Cpu: 8-bit AVR
• # Of Touch Channels: 14
• Hardware Qtouch Acquisition: No
• Max I/o Pins: 26
• Ext Interrupts: 13
• Usb Transceiver: 1
• Usb Speed: Full Speed
• Usb Interface: Device
• Spi: 2
• Twi (i2c): 1
• Uart: 1
• Graphic Lcd: No
• Video Decoder: No
• Camera Interface: No
• Adc Channels: 12
• Adc Resolution (bits): 10
• Adc Speed (ksps): 15
• Analog Comparators: 1
• Resistive Touch Screen: No
• Temp. Sensor: Yes
• Crypto Engine: No
• Sram (kbytes): 3.3
• Eeprom (bytes): 1024
• Self Program Memory: YES
• Dram Memory: No
• Nand Interface: No
• Picopower: No
• Temp. Range (deg C): -40 to 85
• I/o Supply Class: 2.7 to 5.5
• Operating Voltage (vcc): 2.7 to 5.5
• Fpu: No
• Mpu / Mmu: no / no
• Timers: 4
• Output Compare Channels: 12
• Input Capture Channels: 2
• Pwm Channels: 8
• 32khz Rtc: No
• Calibrated Rc Oscillator: Yes

iv
ATmega16/32U4
19 USART in SPI Mode ............................................................................. 214
20 2-wire Serial Interface .......................................................................... 223
21 USB controller ...................................................................................... 253
18.3Frame Formats ....................................................................................................190
18.4USART Initialization ............................................................................................192
18.5Data Transmission – The USART Transmitter ....................................................193
18.6Data Reception – The USART Receiver .............................................................195
18.7Asynchronous Data Reception ............................................................................199
18.8Multi-processor Communication Mode ................................................................202
18.9Hardware Flow Control ........................................................................................203
18.10USART Register Description .............................................................................205
18.11Examples of Baud Rate Setting ........................................................................209
19.1Overview .............................................................................................................214
19.2Clock Generation .................................................................................................214
19.3SPI Data Modes and Timing ...............................................................................215
19.4Frame Formats ....................................................................................................215
19.5Data Transfer ......................................................................................................217
19.6USART MSPIM Register Description ..................................................................219
19.7AVR USART MSPIM vs. AVR SPI ......................................................................221
20.1Features ..............................................................................................................223
20.22-wire Serial Interface Bus Definition ..................................................................223
20.3Data Transfer and Frame Format ........................................................................224
20.4Multi-master Bus Systems, Arbitration and Synchronization ...............................227
20.5Overview of the TWI Module ...............................................................................228
20.6TWI Register Description ....................................................................................231
20.7Using the TWI ......................................................................................................234
20.8Transmission Modes ...........................................................................................238
20.9Multi-master Systems and Arbitration ..................................................................251
21.1Features ..............................................................................................................253
21.2Block Diagram .....................................................................................................253
21.3Typical Application Implementation .....................................................................254
21.4Crystal-less operation ..........................................................................................256
21.5Design guidelines ................................................................................................256
21.6General Operating Modes ...................................................................................257
21.7Power modes ......................................................................................................259
7766F–AVR–11/10