FDC37B78X 查看數據表（PDF） - SMSC -> Microchip

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FDC37B78X

Enhanced Super I/O Controller with ACPI Support, Real Time Clock and Consumer IR

SMSC -> Microchip 

ADD

0h

1h

2h

3h

4h

5h

6h

7h

8h

9h

Dh

7Dh

7Eh

Table 64 - Time, Calendar and Alarm Bytes

REGISTER FUNCTION

BCD RANGE

Register 0: Seconds

00-59

Register 1: Seconds Alarm

00-59

Register 2: Minutes

00-59

Register 3: Minutes Alarm

00-59

Register 4: Hours

01-12 am

(12 hour mode)

81-92 pm

(24 hour mode)

00-23

Register 5: Hours Alarm

01-12 am

(12 hour mode)

81-92 pm

(24 hour mode)

00-23

Register 6: Day of Week

01-07

Register 7: Day of Month

01-31

Register 8: Month

01-12

Register 9: Year

00-99

Date of Month Alarm

1-31

Century Byte

00-99

Control Register 1

BINARY RANGE

00-3B

00-3B

00-3B

00-3B

01-0C

81-8C

00-17

01-0C

81-8C

00-17

01-07

01-1F

01-0C

00-63

01-1F

00-63

Wake-up Alarm Function

The Alarm can be used as a wake-up alarm to

turn on power to the system when the system is

powered off. There are two bits used to control

alarm. The Alarm wake-up function is enabled

via the Alarm Enable bit, AIE. The Alarm

Remember Enable bit, AL_REM_EN, in the RTC

Control Register 1, is used to power-up the

system upon return of power if the Alarm time

has passed during loss of power. These bits

function as follows:

as VTR comes back and the machine will

power-up.

Update Cycle

An update cycle is executed once per second if

the SET bit in Register B is clear and the

DV0-DV2 divider is not clear. The SET bit in the

"1" state permits the program to initialize the

time and calendar bytes by stopping an existing

update and preventing a new one from

occurring.

If VTR is present: AIE controls whether or not

the alarm is enabled as a wake-up function. If

AIE is set and VTR=5V, the nPowerOn pin will

go active (low) when the date/time is equal to

the alarm date/time and the power supply will

turn on the machine.

If VTR is not present: AL_REM_EN controls

whether or not the alarm will power-up the

system upon the return of VTR, regardless of

the value of AIE. If AL_REM_EN is set and

VTR=0 at the date/time that alarm 2 is set for,

the nPowerOn pin will go active (low) as soon

The primary function of the update cycle is to

increment the seconds’ byte, check for overflow,

and increment the minute’s byte when

appropriate and so forth through to the year of

the century byte. The update cycle also

compares each alarm byte with the

corresponding time byte and issues an alarm if

a match or if a "don't care" code is present.

The length of an update cycle is shown in Table

65. During the update cycle, the time, calendar

and alarm bytes are not accessible by the

processor program. If the processor reads these

locations before the update cycle is complete,

141

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