MAXQ3180(2008) Ver la hoja de datos (PDF) - Maxim Integrated

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MAXQ3180
(Rev.:2008)

Low-Power, Multifunction, Polyphase AFE

Maxim Integrated 

Low-Power, Multifunction, Polyphase AFE

VRST1

VPOR

BROWNOUT DETECTION

BROWNOUT DETECTION (ALWAYS

ENABLED OUTSIDE OF STOP MODE)

FORCES RESET STATE. POR = 1

BROWNOUT DETECTION DISABLED

DURING STOP MODE.

NO RESET IS GENERATED.

BROWNOUT DETECTION DISABLED.

POR LEVEL CAUSES RESET.

tPOR

INTERNAL

RESET

STOP MODE

Figure 3. Brownout Reset

error of some kind causes the MAXQ3180 to lock up or

enter an endless execution loop, the watchdog timer

expires and triggers an automatic hardware reset. There

is no register flag to indicate to the master that a watch-

dog reset has occurred, but the RESET line strobes low

briefly. Because the reset causes the MAXQ3180 to re-

enter Initialization Mode, the IRQ line drops low.

The watchdog timer does not run during Stop Mode.

Software Reset

A software reset is initiated by the master by setting the

RST (STATUS0.4) bit to 1. When a software reset

occurs, the MAXQ3180 clears all registers to their

default states and returns to Initialization Mode, in the

same manner as if an external reset had taken place.

Unlike a hardware reset, however, a software reset does

not cause the MAXQ3180 to drive the RESET line low.

Power-Supply Monitoring

In addition to the hardware reset provided by the

power-on reset and brownout reset circuits, the

MAXQ3180 includes the capability to detect a low

power supply on the DVDD pin and alert the master

through the interrupt (IRQ) mechanism before a hard-

ware reset occurs. This function, which is always

enabled outside of Stop Mode, causes the RAM status

register flag PWRF (STATUS1.1) to be set to 1 whenev-

er DVDD drops below the VPFW trip point. Once PWRF

has been set to 1 by hardware, it can only be cleared

by the master (or by a system reset). Whenever PWRF

= 1, if the EPWRF interrupt masking bit is also set to 1,

the MAXQ3180 drives IRQ low to signal to the master

that an interrupt condition (in this case, a power-fail

warning) exists and requires attention.

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