ATmega32U4 Atmel Corporation, ATmega32U4 Datasheet - Page 41

• 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

7766F–AVR–11/10
• Bit 7– PINMUX: PLL Input Multiplexer
This bit selects the clock input of the PLL:
• Bit 6– PLLUSB: PLL Postcaler for USB Peripheral
This bit select the division factor between the PLL output frequency and the USB module input
frequency:
• Bit 5..4 – PLLTM1:0: PLL Postcaler for High Speed Timer
These bits codes for the division factor between the PLL Output Frequency and the High Speed
Timer input frequency.
Note that the division factor 1.5 will introduce some jitter in the clock, but keeping the error null
since the average duty cycle is 50%. See
Figure 6-7.
• Bit 3..0 – PDIV3:0 PLL Lock Frequency
These bits configure the PLL internal VCO clock reference according to the required output fre-
quency value.
Fi
Fi x ---
PLLTM1
PDIV3
0
0
0
0
0
0
0
1
1
2
3
– PINMUX = 0: the PLL input is connected to the PLL Prescaler, that has the Primary
– PINMUX = 1: the PLL input is directly connected to the Internal Calibrated 8MHz RC
– PLLUSB = 0: no division, direct connection (if PLL Output = 48 MHz)
– PLLUSB = 1: PLL Output frequency is divided by 2 and sent to USB module (if PLL
System Clock as source
Oscillator. This mode allows to work in USB Low Speed mode with no crystal or
using a crystal with a value different of 8/16MHz.
Output = 96MHz)
PDIV2
PLLTM0
0
0
0
0
1
PLL Postcaler operation with division factor = 1.5
0
1
0
1
PDIV1
0
0
1
1
0
PLL Postcaler Factor for High-Speed Timer
PDIV0
0
1
0
1
0
0 (Disconnected)
Figure 6-7
PLL Output Frequency
1.5
1
2
Not allowed
Not allowed
Not allowed
for more details.
40 MHz
48 MHz
ATmega16/32U4
41