MAC7101 datasheet(19/56 Pages) FREESCALE

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ElectricalCharacteristics

MAC7100 Microcontroller Family Hardware Specifications, Rev. 1.2

Preliminary

Freescale Semiconductor

3.8.6

Startup

Table 23 summarizes several startup characteristics. Refer to Section 4.3.6.10, “CRG Operating Mode

Details,” in the MAC7100 Microcontroller Family Reference Manual (MAC7100RM) for details.

3.8.6.1

Power On and Low Voltage Reset (POR and LVR)

The VPORR and VPORA levels are derived from VDD2.5. The VLVRA level is derived from VDD2.5. They

are also valid if the device is powered externally. After releasing a POR or LVR reset, the oscillator and

clock quality checks start. After tCQOUT (Table 19, J4) if no valid oscillation is detected, the MCU will

start using the internal self-generated clock. The minimum startup time is given by tuposc (Table 19, J3).

3.8.6.2

SRAM Data Retention

SRAM content integrity is guaranteed if the CRGFLG[PORF] bit is not set following a reset operation.

3.8.6.3

External Reset

When external reset is asserted for a time greater than PWRSTL, the CRG generates an internal reset and

the CPU fetches the reset vector without a clock quality check, if there was stable oscillation before reset.

3.8.6.4

Stop Recovery

The MCU can return from stop to run mode in response to an external interrupt or an API. Two delays

occur before the MCU resumes execution. First, the voltage regulator must exit reduced power mode and

return to full performance mode (this assumes that the internal regulator is used rather than driving VDD2.5

and VDDPLL with an external regulator). Second, a clock quality check is performed in the same manner

as for a power-on reset before releasing the clocks to the system.

3.8.6.5

Pseudo Stop Recovery

Recovery from pseudo stop mode is similar to stop mode in that the VREG must return to FPM, but since

the oscillator is not stopped there is no delay for clock stabilization. The MCU is returned to run mode by

internal or external interrupts.

3.8.6.6

Doze Recovery

Recovery from doze mode avoids both the VREG and oscillator recovery periods. The MCU is returned

to run mode by internal or external interrupts.

Table 23. CRG Startup Characteristics

Num C

Rating

Symbol

Min

Typ

Max

Unit

D Reset input pulse width

PWRSTL

2—

—

tOSC

D Startup from Reset

nRST

192

—

196

tOSC

D XIRQ, IRQ pulse width, edge-sensitive mode

PWIRQ

—

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