PCA5010 datasheet(39/112 Pages) PHILIPS

39 / 112 page

1998 Nov 02

Philips Semiconductors

Product speciﬁcation

Pager baseband controller

PCA5010

6.14

Wake-up counter

6.14.1

FUNCTION

The wake-up counter is intended to be used as protocol

timer. It can be programmed to wake-up the processor

when the protocol needs an action. Amongst others this

may be:

• Switching on the DC/DC converter at time 0

• Enabling the receiver at time 1

• Enabling the demodulator and clock recovery function

at time 2 before relevant data is expected.

The time to wake-up is defined as a 16-bit value containing

the number of 9600 Hz ticks. The maximum time interval

that can be spawn with one cycle then equals 6.8 s.

The wake-up counter and it’s reload latch are supplied by

VBAT and work independent of the 2 V supply. A reset to

the microcontroller does not clear the wake-up counter

control flags or the reload latch, but clears the reload

The counter is implemented as a 16-bit ripple down

counter. It can be loaded from the wake-up reload latch by

a signal from the processor. When the counter is loaded it

automatically starts if the RUN signal is active. When the

counter reaches zero the wake-up signal becomes active

and may generate an interrupt. The wake-up signal

automatically reloads the counter (modulo N counter).

The counter is stopped when the RUN signal is written to

logic 0. Auto reloading of the counter is also possible,

when the DC/DC converter is not operating (i.e. VDD is

below 1.8 V).

The contents of the wake-up counter cannot be read by the

processor. Reading WUC0 and WUC1 reflects the

contents of the 16-bit wake-up register (set by the

microcontroller).

The interface between 2 and 1 V regions is implemented

similar to the clock correction block. The sequence for

writing values is identical (see Fig.16).

Fig.21 Block diagram of wake-up counter.

handbook, full pagewidth

MGR122

STORE

9600 Hz

internal

SET FLAG

SFR to

microcontroller

RESET

with each

OFF cycle

SET

CPL

RUN

LOAD

WUP

TEST

WU0 to WU15

WU RELOAD LATCH

(16-BIT)

reload data

WU COUNTER

(16-BIT)

Interrupt

≥ 1

reload

VDD supply

wake-up DC/DC converter

VBAT supply

CARRY

RESET only

on RESETIN

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