Appendix A Electrical Characteristics
MC9S12XDP512 Data Sheet, Rev. 2.11
944 Freescale Semiconductor
A.5 Reset, Oscillator, and PLL
This section summarizes the electrical characteristics of the various startup scenarios for oscillator and
phase-locked loop (PLL).

A.5.1 Startup

Table A-20 summarizes several startup characteristics explained in this section. Detailed description of the
startup behavior can be found in the Clock and Reset Generator (CRG) Block Guide.

A.5.1.1 POR

The release level VPORR and the assert level VPORA are derived from the VDD supply. They are also valid
if the device is powered externally. After releasing the POR reset the oscillator and the clock quality check
are started. If after a time tCQOUT no valid oscillation is detected, the MCU will start using the internal self
clock. The fastest startup time possible is given by nuposc.

A.5.1.2 SRAM Data Retention

Provided an appropriate external reset signal is applied to the MCU, preventing the CPU from executing
code when VDD35 is out of specification limits, the SRAM contents integrity is guaranteed if after the reset
the PORF bit in the CRG flags register has not been set.

A.5.1.3 External Reset

When external reset is asserted for a time greater than PWRSTL the CRG module generates an internal
reset, and the CPU starts fetching the reset vector without doing a clock quality check, if there was an
oscillation before reset.

A.5.1.4 Stop Recovery

Out of stop the controller can be woken up by an external interrupt. A clock quality check as after POR is
performed before releasing the clocks to the system.
Table A-20. Startup Characteristics
Conditions are shown in Table A-4unless otherwise noted
Num C Rating Symbol Min Typ Max Unit
1 D Reset input pulse width, minimum input time PWRSTL 2—t
osc
2 D Startup from reset nRST 192 196 nosc
3 D Interrupt pulse width, IRQ edge-sensitive mode PWIRQ 20 — ns
4 D Wait recovery startup time tWRS 14 tcyc
5 D Fast wakeup from STOP1
1VDD1/VDD2 filter capacitors 220 nF, VDD35 = 5 V, T= 25°C
tfws —50—µs