LM3S2730 Luminary Micro, Inc, LM3S2730 Datasheet - Page 393

• Manufacturer Part Number: LM3S2730
• Description: Lm3s2730 Arm Microcontroller
• Manufacturer: Luminary Micro, Inc

18.2
18.2.1
18.2.2
July 25, 2008
AC Characteristics
Load Conditions
Unless otherwise specified, the following conditions are true for all timing measurements. Timing
measurements are for 4-mA drive strength.
Figure 18-1. Load Conditions
Clocks
Table 18-6. Phase Locked Loop (PLL) Characteristics
a. The exact value is determined by the crystal value programmed into the XTAL field of the Run-Mode Clock Configuration
b. PLL frequency is automatically calculated by the hardware based on the XTAL field of the RCC register.
Table 18-7. Clock Characteristics
Table 18-8. Crystal Characteristics
Parameter
f
f
f
T
f
f
f
t
f
f
f
Parameter Name
Frequency
Frequency tolerance
Aging
Oscillation mode
Temperature stability (-40°C to 85°C)
Temperature stability (-40°C to 105°C)
ref_crystal
ref_ext
pll
IOSC
IOSC30KHZ
MOSC
MOSC_per
ref_crystal_bypass
ref_ext_bypass
system_clock
READY
Parameter
pin
(RCC) register.
Parameter Name
Crystal reference
External clock reference
PLL frequency
PLL lock time
Parameter Name
Internal 12 MHz oscillator frequency
Internal 30 KHz oscillator frequency
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
GND
C
L
b
= 50 pF
a
a
3.579545
3.579545
Parallel
Min
±50
±25
±25
±5
8
-
-
Preliminary
Parallel
Nom
400
±50
±25
±25
±5
-
-
-
6
Value
8.192
8.192
Max
0.5
Parallel
-
±50
±25
±25
±5
4
MHz
MHz
MHz
Unit
ms
Parallel
±50
±25
±25
3.5
±5
Units
ppm/yr
MHz
ppm
ppm
ppm
-
Min
125
8.4
21
1
1
0
0
Nom
LM3S2730 Microcontroller
12
30
-
-
-
-
-
1000
Max
15.6
39
50
50
8
8
MHz
MHz
MHz
MHz
MHz
Unit
KHz
ns
393