PCA5007 datasheet(35/112 Pages) PHILIPS

35 / 112 page

1998 Oct 07

Philips Semiconductors

Product speciﬁcation

Pager baseband controller

PCA5007

Table 27 RTC Control Register (RTCCON, SFR address CDH)

Table 28 Description of the RTCON bits

6.13.3

REAL-TIME CLOCK DATA REGISTER (RTC0)

Table 29 RTC Data Register (RTC0, SFR address CEH)

The value stored in this SFR is the actual 4 Hz count since the last MINUTE interrupt. The contents of this counter can

be read from and written to by software. The contents of this counter are only initialized when RESETIN is activated.

During an OFF sequence, the RTC continues its operation.

The value of the RTC data register is only updated while the STB flag in the DCCON0 SFR is HIGH, i.e. the DC/DC

converter is able to sustain the VDD supply voltage. If the STB flag is at logic 0 the real-time clock continues its operation,

the MINUTE interrupt occurs regularly, but the SFR is not updated.

76543210

MIN

−−−−

W/R

LOAD

SET

BIT

SYMBOL

FUNCTION

RTCON.7

MIN

MIN is activated when the counter reaches 239. MIN is used to generate the interrupt

request signal MINUTE. In order to complete the interrupt cycle and reset the interrupt

source, the processor has to clear MIN. This must be done in a 2 step operation writing

MIN and then applying a positive edge to SET.

RTCON.6

−

unused

RTCON.5

−

unused

RTCON.4

−

unused

RTCON.3

−

unused

RTCON.2

W/R

Before the RTC time can be set by software, the updating of the SFR by the RTC must

be disabled. This is done by writing the W/R bit to logic 1. The W/R bit is cleared by

hardware after the next 4 Hz clock, when the RTC has been loaded with its next value.

RTCON.1

LOAD

Load RTC with contents of RTC0. LOAD is sampled with the positive edge of the set

ﬂag SET. If LOAD is not HIGH during a SET operation, only the MIN ﬂag is (re)set by the

command.

RTCON.0

SET

Latch signal for the real-time clock. With the pulse on SET the content of MIN is

copied into the ‘real’ MIN latch. This is necessary because the RTC has to be active at

all times independant of the microcontroller.

76543210

QSECS7

QSECS6

QSECS5

QSECS4

QSECS3

QSECS2

QSECS1

QSECS0

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