AT90USB1286-16MU ATMEL [ATMEL Corporation], AT90USB1286-16MU Datasheet - Page 50

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

6.11.2
50
AT90USB64/128
PLL Control and Status Register – PLLCSR
Figure 6-4.
• Bit 7..5 – Res: Reserved Bits
These bits are reserved bits in the AT90USB64/128 and always read as zero.
• Bit 4..2 – PLLP2:0 PLL prescaler
These bits allow to configure the PLL input prescaler to generate the 2MHz input clock for the
PLL.
Table 6-13.
• Bit 1 – PLLE: PLL Enable
When the PLLE is set, the PLL is started.
Bit
$29 ($29)
Read/Write
Initial Value
PLLP2
0
0
0
0
1
1
1
1
XTAL1
XTAL2
7
R
0
PLL Clocking System
PLL input prescaler configurations
PLLP1
RC OSCILLATOR
Watchdog
8 MHz
OSCILLATOR
OSCILLATORS
0
0
1
1
0
0
1
1
6
R
0
PLL clock
Prescaler
PLLP0
5
R
0
0
1
0
1
0
1
0
1
0
4
PLLP2
R
clk
2MHz
Clock Division
Reserved
Reserved
Factor
PLL
3
PLLP1
R
0
PLLE
24x
1
2
3
4
6
8
Detector
Lock
2
PLLP0
R
0
External XTAL required for USB
PLOCK
1
PLLE
R/W
0/1
operation (MHz)
clk USB (48MHz)
0
PLOCK
R
0
12
16
2
4
6
8
-
-
7593A–AVR–02/06
System Clock
PLLCSR