ATmega16U2 Atmel Corporation, ATmega16U2 Datasheet - Page 40

• Manufacturer Part Number: ATmega16U2
• Manufacturer: Atmel Corporation

Specifications of ATmega16U2

• Flash (kbytes): 16 Kbytes
• Pin Count: 32
• Max. Operating Frequency: 16 MHz
• Cpu: 8-bit AVR
• # Of Touch Channels: 12
• Hardware Qtouch Acquisition: No
• Max I/o Pins: 22
• Ext Interrupts: 21
• Usb Transceiver: 1
• Usb Speed: Full Speed
• Usb Interface: Device
• Spi: 2
• Uart: 1
• Graphic Lcd: No
• Video Decoder: No
• Camera Interface: No
• Analog Comparators: 1
• Resistive Touch Screen: No
• Temp. Sensor: No
• Crypto Engine: No
• Sram (kbytes): 0.5
• Eeprom (bytes): 512
• 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: 2
• Output Compare Channels: 5
• Input Capture Channels: 1
• Pwm Channels: 4
• 32khz Rtc: No
• Calibrated Rc Oscillator: Yes

8.11.6
7799D–AVR–11/10
PLLCSR – PLL Control and Status Register
Table 8-9.
• Bit 7:5 – Res: Reserved Bits
These bits are reserved bits in the ATmega8U2/16U2/32U2 and always read as zero.
• Bit 4 – DIV5 PLL Input Prescaler (1:5)
• Bit 3 – DIV3 PLL Input Prescaler (1:3)
• Bit 2 – PINDIV PLL Input Prescaler (1:1, 1:2)
These bits allow to configure the PLL input prescaler to generate the 8MHz input clock for the
PLL from either a 8 or 16 MHz input.
When using a 8 MHz clock source, this bit must be set to 0 before enabling PLL (1:1).
When using a 16 MHz clock source, this bit must be set to 1 before enabling PLL (1:2).
• Bit 3:2 – Res: Reserved Bits
These bits are reserved and always read as zero.
Bit
0x29 (0x49)
Read/Write
Initial Value
CLKPS3
0
0
0
0
0
0
0
0
1
1
1
1
1
1
1
1
Clock Prescaler Select
R
7
–
0
CLKPS2
0
0
0
0
1
1
1
1
0
0
0
0
1
1
1
1
R
6
–
0
CLKPS1
R
5
–
0
0
0
1
1
0
0
1
1
0
0
1
1
0
0
1
1
DIV5
R/W
4
0
CLKPS0
ATmega8U2/16U2/32U2
DIV3
R
3
0
0
1
0
1
0
1
0
1
0
1
0
1
0
1
0
1
PINDIV
R
2
0
Clock Division Factor
PLLE
R/W
1
0
Reserved
Reserved
Reserved
Reserved
Reserved
Reserved
Reserved
PLOCK
128
256
16
32
64
1
2
4
8
R
0
0
PLLCSR
40