Philips Semiconductors

 

 

 

 

User’s Manual - Preliminary -

 

 

 

 

 

 

 

 

 

REAL-TIME CLOCK/SYSTEM TIMER

P89LPC906/907/908

 

 

 

 

 

 

 

 

 

FOSC2

FOSC1

FOSC0

RTCS1:0

 

 

 

 

 

(UCFG1.2)

(UCFG1.1)

(UCFG1.0)

CCLK Frequency

 

RTC Clock Frequency

 

 

 

 

 

 

 

 

 

 

 

 

 

00

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

01

 

 

undefined

 

 

1

0

0

 

WDT Oscillator/DIVM

 

 

 

 

10

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

11

 

 

WDT Oscillator/DIVM

 

 

 

 

 

 

 

(CCLK)

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

1

0

1

 

 

 

 

 

 

 

 

 

 

 

 

 

 

1

1

0

xx

undefined

 

 

 

 

 

 

 

 

 

 

 

 

1

1

1

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

CHANGING RTCS1-0

RTCS1-0 cannot be changed if the RTC is currently enabled (RTCCON.0 =1). Setting RTCEN and updating RTCS1-0 may be done in a single write to RTCCON. However, if RTCEN = 1, this bit must first be cleared before updating RTCS1-0

REAL-TIME CLOCK INTERRUPT/WAKE UP

If ERTC (RTCCON.1), EWDRT (IEN0.6) and EA (IEN0.7) are set to ’1’, RTCF can be used as an interrupt source. This interrupt vector is shared with the watchdog timer. It can also be a source to wake up the device.

RESET SOURCES AFFECTING THE REAL-TIME CLOCK

Only power-on reset will reset the Real-time Clock and its associated SFRs to their default state.

2003 Dec 8

50

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Image 50
Philips P89LPC907 Changing RTCS1-0, REAL-TIME Clock INTERRUPT/WAKE UP, Reset Sources Affecting the REAL-TIME Clock