MSP430F2101 Datasheet, PDF (26/53 Pages) Texas Instruments – MIXED SIGNAL MICROCONTROLLER

MSP430x21x1
MIXED SIGNAL MICROCONTROLLER
SLAS439C − SEPTEMBER 2004 − REVISED JULY 2006
electrical characteristics over recommended ranges of supply voltage and operating free-air
temperature (unless otherwise noted) (continued)
crystal oscillator, LFXT1, low frequency modes (see Note 4)
PARAMETER
TEST CONDITIONS
VCC
MIN TYP MAX UNIT
fLFXT1,LF
LFXT1 oscillator crystal
frequency, LF mode 0, 1
XTS = 0, LFXT1Sx = 0 or 1
1.8 V − 3.6 V
32,768
Hz
LFXT1 oscillator logic level
fLFXT1,LF,logic square wave input frequency,
LF mode
XTS = 0, LFXT1Sx = 3
1.8 V − 3.6 V 10,000 32,768 50,000 Hz
OALF
CL,eff
Oscillation Allowance for LF
crystals
Integrated effective Load
Capacitance, LF mode
(see Note 1)
XTS = 0, LFXT1Sx = 0;
fLFXT1,LF = 32,768 kHz,
CL,eff = 6 pF
XTS = 0, LFXT1Sx = 0;
fLFXT1,LF = 32,768 kHz,
CL,eff = 12 pF
XTS = 0, XCAPx = 0
XTS = 0, XCAPx = 1
XTS = 0, XCAPx = 2
XTS = 0, XCAPx = 3
500
kW
200
kW
1
pF
5.5
pF
8.5
pF
11
pF
Duty Cycle LF mode
XTS = 0, Measured at
P1.4/ACLK, fLFXT1,LF = 32,768
Hz
2.2 V/3 V
30
50
70 %
fFault,LF
Oscillator fault frequency, LF
mode (see Note 3)
XTS = 0, LFXT1Sx = 3
(see Notes 2)
2.2 V/3 V
10
10,000 Hz
NOTES:
1. Includes parasitic bond and package capacitance (approximately 2pF per pin).
Since the PCB adds additional capacitance it is recommended to verify the correct load by measuring the ACLK frequency. For a
correct setup the effective load capacitance should always match the specification of the used crystal.
2. Measured with logic level input frequency but also applies to operation with crystals.
3. Frequencies below the MIN specification will set the fault flag, frequencies above the MAX specification will not set the fault flag.
Frequencies in between might set the flag.
4. To improve EMI on the LFXT1 oscillator the following guidelines should be observed.
− Keep as short of a trace as possible between the device and the crystal.
− Design a good ground plane around the oscillator pins.
− Prevent crosstalk from other clock or data lines into oscillator pins XIN and XOUT.
− Avoid running PCB traces underneath or adjacent to the XIN and XOUT pins.
− Use assembly materials and praxis to avoid any parasitic load on the oscillator XIN and XOUT pins.
− If conformal coating is used, ensure that it does not induce capacitive/resistive leakage between the oscillator pins.
− Do not route the XOUT line to the JTAG header to support the serial programming adapter as shown in other
documentation. This signal is no longer required for the serial programming adapter.
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