Power-On Detection; Brownout Options - Philips P89LPC902 User Manual

Philips Semiconductors
POWER MONITORING FUNCTIONS
BOE PMOD1-0
(UCFG1.5) (PCON.1-0)
0 (erased) XX
11 (total
power down)
≠ 11(any
1 (programmed)
mode other
than total
power down)
Table 7-1: Brownout Options.

Power-On Detection

The Power-On Detect has a function similar to the Brownout Detect, but is designed to work as power initially comes up, before
the power supply voltage reaches a level where the Brownout Detect can function. The POF flag (RSTSRC.4) is set to indicate
an initial power-on condition. The POF flag will remain set until cleared by software by writing '0' to the bit. Note that if BOE
(UCFG1.5) is programmed, BOF (RSTSRC.5) will be set when POF is set. If BOE is unprogrammed, BOF is meaningless.
2003 Dec 8
BOPD BOI EBO
(PCON.5) (PCON.4) (IEN0.5)
X X
X X
1
(brownout
detect X
powered
down)
0
(brownout
detect
generates
reset)
0
(brownout (enable
1
detect brownout
(brownout
active) interrupt)
detect
generates
an
interrupt)
EA
(IEN0.7)
X X
Brownout disabled. V
X X
Brownout disabled. V
X X
However, BOPD is default to '0' upon power-up.
Brownout reset enabled. V
3.6V. Upon a brownout reset, BOF (RSTSRC.5) will be
X X
set to indicate the reset source. BOF can be cleared by
writing '0' to the bit.
1 1
Brownout interrupt enabled. V
(global
3.6V. Upon a brownout interrupt, BOF (RSTSRC.5) will
interrupt
be set. BOF can be cleared by writing '0' to the bit.
enable)
0 X Both brownout reset and interrupt disabled. V
operating range is 2.4V-3.6V. However, BOF
(RSTSRC.5) will be set when V
X 0
Detection trip point. BOF can be cleared by writing '0' to
the bit.
56
User's Manual - Preliminary -
P89LPC901/902/903
Description
operating range is 2.4V-3.6V.
DD
operating range is 2.4V-3.6V.
DD
operating range is 2.7V-
DD
operating range is 2.7V-
DD
DD
falls to the Brownout
DD