AT90USB1286-16MU ATMEL [ATMEL Corporation], AT90USB1286-16MU Datasheet - Page 49

• Manufacturer Part Number: AT90USB1286-16MU
• Description: Microcontroller with 64/128K Bytes of ISP Flash and USB Controller
• Manufacturer: ATMEL [ATMEL Corporation]

6.11
6.11.1
7593A–AVR–02/06
PLL
Internal PLL for USB interface
Table 6-12.
The PLL is used to generate internal high frequency (48 MHz) clock for USB interface, the PLL
input is generated from an external low-frequency (the crystal oscillator or external clock input
pin from XTAL1).
The internal PLL in AT90USB64/128 generates a clock frequency that is 24x multiplied from
nominally 2 MHz input. The source of the 2 MHz PLL input clock is the output of the internal PLL
clock prescaler that generates the 2 MHz (See
CLKPS3
0
0
0
0
0
0
0
0
1
1
1
1
1
1
1
1
Clock Prescaler Select
CLKPS2
0
0
0
0
1
1
1
1
0
0
0
0
1
1
1
1
CLKPS1
0
0
1
1
0
0
1
1
0
0
1
1
0
0
1
1
CLKPS0
Section 6.11.2
0
1
0
1
0
1
0
1
0
1
0
1
0
1
0
1
Clock Division Factor
for PLL interface).
AT90USB64/128
Reserved
Reserved
Reserved
Reserved
Reserved
Reserved
Reserved
128
256
16
32
64
1
2
4
8
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