LM3S328 Luminary Micro, Inc., LM3S328 Datasheet - Page 77

• Manufacturer Part Number: LM3S328
• Description: Microcontroller
• Manufacturer: Luminary Micro, Inc.

October 8, 2006
Bit/Field
26:23
21:14
22
13
12
USESYSDIV
reserved
PWRDN
SYSDIV
Name
OEN
Type
R/W
R/W
R/W
R/W
RO
Reset
0xF
0
1
1
0
Preliminary
Description
System Clock Divisor
Specifies which divisor is used to generate the system clock
from the PLL output (200 MHz).
When reading the Run-Mode Clock Configuration (RCC)
register (see page 76), the SYSDIV value is MINSYSDIV if
a lower divider was requested and the PLL is being used.
This lower value is allowed to divide a non-PLL source.
clock. The system clock divider is forced to be used when
the PLL is selected as the source.
Reserved bits return an indeterminate value, and should
never be changed.
PLL Power Down
This bit connects to the PLL PWRDN input. The reset value
of 1 powers down the PLL. See Table 6-4 on page 79 for
PLL mode control.
PLL Output Enable
This bit specifies whether the PLL output driver is enabled.
If cleared, the driver transmits the PLL clock to the output.
Otherwise, the PLL clock does not oscillate outside the PLL
module.
Note:
Use the system clock divider as the source for the system
Binary
Value
0000
0001
0010
0100
0101
1000
1001
1010
0011
0110
0111
1011
1100
1101
1110
1111
Both PWRDN and OEN must be cleared to run the
PLL.
Divisor
(BYPASS=1)
reserved
/2
/3
/4
/5
/6
/7
/8
/9
/10
/11
/12
/13
/14
/15
/16
Frequency
(BYPASS=0)
reserved
reserved
reserved
reserved
reserved
reserved
reserved
25 MHz
22.22 MHz
20 MHz
18.18 MHz
16.67 MHz
15.38 MHz
14.29 MHz
13.33 MHz
12.5 MHz (default)
LM3S328 Data Sheet
77