MC3S12RG128 Datasheet, PDF (524/546 Pages) Freescale Semiconductor, Inc – Microcontrollers

Appendix A Electrical Characteristics
Table A-15. Voltage Regulator - Capacitive Loads
Num
Characteristic
1
V_DD external capacitive load
2
V_DDPLL external capacitive load
Symbol
Min
C_DDext
400
C_DDPLLext
90
Typical
440
220
Max
Unit
12000
nF
5000
nF
A.6 Reset, Oscillator and PLL
This section summarizes the electrical characteristics of the various startup scenarios for Oscillator and
Phase-Locked-Loop (PLL).
A.6.1 Startup
Table A-16 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 User Guide.
Table A-16. Startup Characteristics
Conditions are shown in Table A-4 unless otherwise noted
Num C
Rating
Symbol
Min
Typ
Max
Unit
1 D Reset input pulse width, minimum input time
2 D Startup from Reset
3 D Interrupt pulse width, IRQ edge-sensitive mode
4 D Wait recovery startup time
PW_RSTL
2
n_RST
192
PW_IRQ
20
t_WRS
t_osc
196
n_osc
ns
14
t_cyc
A.6.1.1 POR
Both the deassert level V_PORD and the assert level V_PORA (Table A-14) are derived from the V_DD 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 t_CQOUT no valid oscillation is detected, the MCU will start
using the internal self clock. The fastest startup time possible is given by n_uposc.
A.6.1.2 SRAM Data Retention
Provided an appropriate external reset signal is applied to the MCU, preventing the CPU from executing
code if V_DD35 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.6.1.3 External Reset
When external reset is asserted for a time greater than PW_RSTL 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.
MC3S12RG128 Data Sheet, Rev. 1.05
524
Freescale Semiconductor