Справочник Пользователя для Freescale Semiconductor Demonstration Board for Freescale MC9S12XHY256 Microcontroller DEMO9S12XHY256 DEMO9S12XHY256

748

Freescale Semiconductor

With each transition of the clock f

cmp

, the deviation from the reference clock f

ref

 is measured and input

voltage to the VCO is adjusted accordingly.The adjustment is done continuously with no abrupt changes
in the clock output frequency. Noise, voltage, temperature and other factors cause slight variations in the

Conditions are shown in Table A-4. unless otherwise noted

1a

C Crystal oscillator range (loop controlled Pierce)

f

OSC

4.0

—

16

MHz

2

P Startup Current

i

OSC

100

—

—

µ

A

3a

C Oscillator start-up time (LCP, 4 MHz)

1

1

These values apply for carefully designed PCB layouts with capacitors that match the crystal/resonator requirements..

t

UPOSC

—

2.2

10

ms

3b

C Oscillator start-up time (LCP, 8 MHz)

t

UPOSC

—

1.1

8

ms

3c

C Oscillator start-up time (LCP, 16 MHz)

t

UPOSC

—

0.75

5

ms

5

D Clock Quality check time-out

t

CQOUT

0.45

—

2.5

s

6

P Clock Monitor Failure Assert Frequency

f

CMFA

200

400

800

kHz

7

P External square wave input frequency

f

EXT

2.0

—

50

MHz

8

D External square wave pulse width low

t

EXTL

9.5

—

—

ns

9

D External square wave pulse width high

t

EXTH

9.5

—

—

ns

10

D External square wave rise time

t

EXTR

—

—

1

ns

11

D External square wave fall time

t

EXTF

—

—

1

ns

12

D Input Capacitance (EXTAL, XTAL pins)

C

IN

—

7

—

pF

13

P EXTAL Pin Input High Voltage

V

IH,EXTAL

0.75*V

DDPLL

—

—

V

T EXTAL Pin Input High Voltage

2

Only applies if EXTAL is externally driven

V

IH,EXTAL

—

—

V

DDPLL

+ 0.3

V

14

P EXTAL Pin Input Low Voltage

V

IL,EXTAL

—

—

0.25*V

DDPLL

V

T

EXTAL Pin Input Low Voltage

V

IL,EXTAL

V

SSPLL

 - 0.3

—

—

V

15

C EXTAL Pin Input Hysteresis

V

HYS,EXTAL

—

180

—

mV

16

C

EXTAL Pin oscillation amplitude (loop controlled
Pierce)

V

PP,EXTAL

—

0.9

—

V