PCD3745A datasheet(9/32 Pages) PHILIPS

9 / 32 page

1999 Feb 02

Philips Semiconductors

Product speciﬁcation

8-bit microcontroller with 4.5 kbytes OTP

memory and 32 kHz real-time clock

PCD3745A

6.4

Clock Control Register (CLCR)

Table 3

Clock Control Register (address 20H)

Table 4

Description of CLCR bits

6.5

Frequency Adjustment Register (FAR)

Table 5

Frequency Adjustment Register (address 21H)

Table 6

Description of FAR bits

76543210

SITS

TST2

TST1

ERCO

RUN

ITS

CIF

ECI

BIT

SYMBOL

DESCRIPTION

SITS

Second Interrupt Time Select. If SITS = 1 and ITS = 1, then the interrupt time is

1.5 seconds.

TST2

Test 2 input. This is a test bit and must be ﬁxed at zero by user software.

TST1

Test 1 input. This is a test bit and must be ﬁxed at zero by user software.

ERCO

Enable 16 kHz Clock Output. If ERCO = 0, then P1.7/RCO is a port line. If ERCO = 1,

then P1.7/RCO is a 16 kHz clock output. The port instructions for P1.7/RCO are not

inhibited and therefore the state of both the port line and flip-flop may be read in and the

port flip-flop may be written to by port instructions.

RUN

Clock Run/Stop. If RUN = 0, then the 32 kHz oscillator is stopped and the divider chain

is reset. If RUN = 1, then the 32 kHz oscillator and the divider chain are running.

ITS

Interrupt Time Select. If ITS = 1 and SITS = 0, then the interrupt time is one second. If

ITS = 0 and SITS = X, then the interrupt time is one minute.

CIF

Clock Interrupt Flag. Set by hardware, if RTC divider chain overﬂows (every second,

1.5 second or minute depending on ITS) or by software. Reset: by software.

ECI

Enable Clock Interrupt. If ECI = 0, the RTC interrupt is disabled. If ECI = 1, the RTC

interrupt is enabled.

76543210

FAR7

FAR6

FAR5

FAR4

FAR3

FAR2

FAR1

FAR0

BIT

SYMBOL

DESCRIPTION

FAR7

The state of these 8-bits determine the frequency adjustment value for the real-time

clock section; see Table 7.

FAR6

FAR5

FAR4

FAR3

FAR2

FAR1

FAR0

PCD3745A Datasheet(PDF) 9 Page - NXP Semiconductors

PCD3745A Datasheet(HTML) 9 Page - NXP Semiconductors

Html Pages

1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 26 27 28 29 30 31 32

Datasheet Descarga

Enlace URL