MC9S12DT128CPVE Datasheet, PDF (108/128 Pages) Freescale Semiconductor, Inc – Device User Guide

MC9S12DT128B Device User G^Fu^rid^ee^e—^sV^c0^a1.^l0^e9 ^{Semiconductor, Inc.}
A.5.1.5 Pseudo Stop and Wait Recovery
The recovery from Pseudo STOP and Wait are essentially the same since the oscillator was not stopped in
both modes. The controller can be woken up by internal or external interrupts. After t_wrs the CPU starts
fetching the interrupt vector.
A.5.2 Oscillator
The device features an internal Colpitts and Pierce oscillator. The selection of Colpitts oscillator or Pierce
oscillator/external clock depends on the XCLKS signal which is sampled during reset.By asserting the
XCLKS input during reset this oscillator can be bypassed allowing the input of a square wave. Before
asserting the oscillator to the internal system clocks the quality of the oscillation is checked for each start
from either power-on, STOP or oscillator fail. t_CQOUT specifies the maximum time before switching to the
internal self clock mode after POR or STOP if a proper oscillation is not detected. The quality check also
determines the minimum oscillator start-up time t_UPOSC. The device also features a clock monitor. A
Clock Monitor Failure is asserted if the frequency of the incoming clock signal is below the Assert
Frequency f_CMFA.
Table A-15 Oscillator Characteristics
Conditions are shown in Table A-4 unless otherwise noted
Num C
Rating
Symbol Min
1a C Crystal oscillator range (Colpitts)
f_OSC
0.5
1b C _{Crystal oscillator range (Pierce)} ¹
f_OSC
0.5
2 P Startup Current
i_OSC
100
3 C Oscillator start-up time (Colpitts)
t_UPOSC
4 D Clock Quality check time-out
t_CQOUT
0.45
5 P Clock Monitor Failure Assert Frequency
f_CMFA
50
6 P _{External square wave input frequency} ⁴
f_EXT
0.5
7 D External square wave pulse width low
t_EXTL
9.5
8 D External square wave pulse width high
t_EXTH
9.5
9 D External square wave rise time
t_EXTR
10 D External square wave fall time
t_EXTF
11 D Input Capacitance (EXTAL, XTAL pins)
C_IN
12
C
DC Operating Bias in Colpitts Configuration on
EXTAL Pin
V_DCBIAS
NOTES:
1. Depending on the crystal a damping series resistor might be necessary
2. f_osc = 4MHz, C = 22pF.
3. Maximum value is for extreme cases using high Q, low frequency crystals
4. XCLKS =0 during reset
Typ
8²
100
7
1.1
Max
16
40
100³
2.5
200
50
1
1
Unit
MHz
MHz
µA
ms
s
KHz
MHz
ns
ns
ns
ns
pF
V
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