ATMEGA16U4-MU Atmel, ATMEGA16U4-MU Datasheet - Page 41

• Manufacturer Part Number: ATMEGA16U4-MU
• Description: MCU AVR 16K FLASH 16MHZ 44-QFN
• Manufacturer: Atmel
• Series: AVR® ATmegar

Specifications of ATMEGA16U4-MU

• Core Processor: AVR
• Core Size: 8-Bit
• Speed: 16MHz
• Connectivity: I²C, SPI, UART/USART, USB
• Peripherals: Brown-out Detect/Reset, POR, PWM, Temp Sensor, WDT
• Number Of I /o: 26
• Program Memory Size: 16KB (8K x 16)
• Program Memory Type: FLASH
• Eeprom Size: 512 x 8
• Ram Size: 1.25K 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
• For Use With: ATSTK600 - 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: ATMEGA16U4-16MU; ATMEGA16U4-16MU

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
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