LM3S1601 Datasheet, PDF (545/587 Pages) Texas Instruments – ARM and Thumb are registered trademarks and Cortex is a trademark

Stellaris^® LM3S1601 Microcontroller
18.2.2
Clocks
Table 18-8. Phase Locked Loop (PLL) Characteristics
Parameter Parameter Name
Min
Nom
Max
Unit
f_{ref_crystal}
f_{ref_ext}
f_pll
Crystal reference^a
External clock reference^a
PLL frequency^b
3.579545
-
3.579545
-
-
400
8.192
8.192
-
MHz
MHz
MHz
T_READY
PLL lock time
-
-
0.5
ms
a. The exact value is determined by the crystal value programmed into the XTAL field of the Run-Mode Clock Configuration
(RCC) register.
b. PLL frequency is automatically calculated by the hardware based on the XTAL field of the RCC register.
Table 18-9 on page 545 shows the actual frequency of the PLL based on the crystal frequency used
(defined by the XTAL field in the RCC register).
Table 18-9. Actual PLL Frequency
XTAL
0x4
0x5
0x6
0x7
0x8
0x9
0xA
0xB
0xC
0xD
0xE
0xF
Crystal Frequency (MHz)
3.5795
3.6864
4.0
4.096
4.9152
5.0
5.12
6.0
6.144
7.3728
8.0
8.192
PLL Frequency (MHz)
400.904
398.1312
400
401.408
398.1312
400
399.36
400
399.36
398.1312
400
398.6773333
Error
0.0023%
0.0047%
-
0.0035%
0.0047%
-
0.0016%
-
0.0016%
0.0047%
0.0047%
0.0033%
Table 18-10. Clock Characteristics
Parameter
f_IOSC
f_IOSC30KHZ
f_XOSC
f_{XOSC_XTAL}
f_{XOSC_EXT}
f_MOSC
t_{MOSC_per}
f_{ref_crystal_bypass}
f_{ref_ext_bypass}
f_{system_clock}
Parameter Name
Internal 12 MHz oscillator frequency
Internal 30 KHz oscillator frequency
Hibernation module oscillator frequency
Crystal reference for hibernation oscillator
External clock reference for hibernation
module
Main oscillator frequency
Main oscillator period
Crystal reference using the main oscillator
(PLL in BYPASS mode)
External clock reference (PLL in BYPASS
mode)
System clock
Min
Nom
8.4
12
15
30
-
4.194304
-
4.194304
-
32.768
1
-
125
-
1
-
0
-
0
-
Max
15.6
45
-
-
-
8.192
1000
8.192
50
50
Unit
MHz
KHz
MHz
MHz
KHz
MHz
ns
MHz
MHz
MHz
June 19, 2012
545
Texas Instruments-Production Data