Micro Crystal

Real Time Clock / Calendar Module

RV-8564

14/40

8.4.4.WEEKDAY ALARM (address 0Ch…bits description)

Address

Function

Bit 7

Bit 6

Bit 5

Bit 4

Bit 3

Bit 2

Bit 1

Bit 0

0Ch

Weekday Alarm

AE_W

X

X

X

X

4

2

1

Bit

Symbol

Value

Description

7

AE_W

0

Weekday Alarm in enabled

1

1)

Weekday Alarm is disabled

6 to 3

X

-

Unused

2 to 0

Weekday Alarm

0 to 6

Weekday Alarm information coded in BCD format

8.5. CLKOUT REGISTER

A programmable square wave output is available at CLKOUT pin. Operation is controlled by the FE bit in register

CLKOUT Frequency and Clock Output Enable pin (CLKOE). To enable CLKOUT, CLKOE pin must be set HIGH.

Frequencies of 32.768 kHz (default), 1024 Hz, 32 Hz and 1 Hz can be generated for use as a system clock,

microcontroller clock, input to a charge pump, or for calibration of the oscillator.

8.5.1.CLKOUT FREQUENCY (address 0Dh…bits description)

Address

Function

Bit 7

Bit 6

Bit 5

Bit 4

Bit 3

Bit 2

Bit 1

Bit 0

0Dh

CLKOUT Frequency

FE

X

X

X

X

X

FD1

FD0

Bit

Symbol

Value

Description

7

FE

0

The CLKOUT output is inhibited and set to logic 0

1

1)

The CLKOUT output is activated

6 to 2

X

-

Unused

1 to 0

FD[1:0]

00

CLKOUT Frequency selection

CLKOUT Frequency

Bit 7

Bit 6

Bit 5

Bit 4

Bit 3

Bit 2

Bit 1

Bit 0

32.768 kHz

X

X

X

X

X

X

0

0

1024 Hz

X

X

X

X

X

X

0

1

32 Hz

X

X

X

X

X

X

1

0

1 Hz

X

X

X

X

X

X

1

1

8.6. TIMER REGISTER

The 8-bit countdown timer register at address 0Fh is controlled by the timer control register at address 0Eh. The

Timer Control register determines one of 4 source clock frequencies for the timer (4096 Hz, 64 Hz, 1 sec, or 1/60

Hz) and enables / disables the timer. The timer counts down from a software loaded 8-bit binary value. At the end

of every countdown, the timer sets the Timer Flag TF to logic 1. The TF may only be cleared using the interface.

The generation of interrupts from the timer function is controlled via bit TIE (Control / Status 2 register). If bit TIE is

enabled, the INT pin follows the condition of bit TF. The interrupt may be generated as a pulsed signal every

countdown period or as a permanent active signal which follows the condition of the Timer Flag TF. TI/TP (Control /

Status 2 register) is used for this mode control. When reading the timer, the current countdown value is returned.