LM3S9792 Datasheet, PDF (138/1279 Pages) Texas Instruments – Stellaris® LM3S9792 Microcontroller

System Control
Bit/Field
28:23
22
21:15
14
13
12
11
10:7
Name
SYSDIV2
SYSDIV2LSB
reserved
USBPWRDN
PWRDN2
reserved
BYPASS2
reserved
Type
R/W
R/W
RO
R/W
R/W
RO
R/W
RO
Reset
0x0F
1
0x0
1
Description
System Clock Divisor 2
Specifies which divisor is used to generate the system clock from either
the PLL output or the oscillator source (depending on how the BYPASS2
bit is configured). SYSDIV2 is used for the divisor when both the
USESYSDIV bit in the RCC register and the USERCC2 bit in this register
are set. See Table 6-6 on page 111 for programming guidelines.
Additional LSB for SYSDIV2
When DIV400 is set, this bit becomes the LSB of SYSDIV2. If DIV400
is clear, this bit is not used. See Table 6-6 on page 111 for programming
guidelines.
This bit can only be set or cleared when DIV400 is set.
Software should not rely on the value of a reserved bit. To provide
compatibility with future products, the value of a reserved bit should be
preserved across a read-modify-write operation.
Power-Down USB PLL
Value Description
1 The USB PLL is powered down.
0 The USB PLL operates normally.
1
Power-Down PLL 2
Value Description
1 The PLL is powered down.
0 The PLL operates normally.
0
Software should not rely on the value of a reserved bit. To provide
compatibility with future products, the value of a reserved bit should be
preserved across a read-modify-write operation.
1
PLL Bypass 2
Value Description
1 The system clock is derived from the OSC source and divided
by the divisor specified by SYSDIV2.
0 The system clock is the PLL output clock divided by the divisor
specified by SYSDIV2.
See Table 6-6 on page 111 for programming guidelines.
Note: The ADC must be clocked from the PLL or directly from a
16-MHz clock source to operate properly.
0x0
Software should not rely on the value of a reserved bit. To provide
compatibility with future products, the value of a reserved bit should be
preserved across a read-modify-write operation.
138
June 14, 2010
Texas Instruments-Advance Information