LM3S2276 Datasheet, PDF (724/785 Pages) Texas Instruments – Stellaris® LM3S2276 Microcontroller

Electrical Characteristics
21.2.2
Clocks
Table 21-8. 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
16.384
16.384
-
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 21-9 on page 724 shows the actual frequency of the PLL based on the crystal frequency used
(defined by the XTAL field in the RCC register).
Table 21-9. Actual PLL Frequency
XTAL
0x04
0x05
0x06
0x07
0x08
0x09
0x0A
0x0B
0x0C
0x0D
0x0E
0x0F
0x10
0x11
0x12
0x13
0x14
0x15
0x16
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
10.0
12.0
12.288
13.56
14.318
16.0
16.384
PLL Frequency (MHz)
400.904
398.1312
400
401.408
398.1312
400
399.36
400
399.36
398.1312
400
398.6773333
400
400
401.408
397.76
400.90904
400
404.1386667
Error
0.0023%
0.0047%
-
0.0035%
0.0047%
-
0.0016%
-
0.0016%
0.0047%
0.0047%
0.0033%
-
-
0.0035%
0.0056%
0.0023%
-
0.010%
Table 21-10. Clock Characteristics
Parameter
f_IOSC
f_IOSC30KHZ
f_XOSC
f_{XOSC_XTAL}
f_{XOSC_EXT}
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
Min
Nom
8.4
12
15
30
-
4.194304
-
4.194304
-
32.768
Max
15.6
45
-
-
-
Unit
MHz
KHz
MHz
MHz
KHz
724
November 17, 2011
Texas Instruments-Production Data