MFC2000 datasheet(347/426 Pages) ETC

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Hardware Description

MFC 2000 Multifunctional Peripheral Controller 2000

100723A

Conexant

18-3

Address:

Bit 15

Bit 14

Bit 13

Bit 12

Bit 11

Bit 10

Bit 9

Bit 8

Default:

Real Time Clock Ctrl

(RTC)

01FF8097

(Not Used)

Rst. Value

xxh

Read Value

00h

Address:

Bit 7

Bit 6

Bit 5

Bit 4

Bit 3

Bit 2

Bit 1

Bit 0

Default:

Real Time Clock Ctrl

(RTC)

01FF8096

Read: Clears the busy flag (data is undefined)

Write: Resets the Real Time Clock (RTC), (data is a don't care)

Rst. Value

xxh

Read Value

00h

Read: clear BUSY flag, data is undefined. Write: reset the RTC, data is 'don't care'.

18.3 RTC Operations

18.3.1 Power-Up/Power-Down Operation

When prime power is applied to the MFPC and battery reset (BATRSTn) is generated, all counters in the RTC are

reset to 0 and the RTC becomes accessible after a delay of from 125 to 250 ms, provided that the crystal clock is

running. (Note: The RTC is also software resetable.)

When prime power drops below a level where the power-down input (PWRDWNn) becomes active, an internal

lockout signal prevents read and write access of the RTC, and RTC operation switches to battery power.

Inactivation of the PWRDWNn pin (when prime power is restored) removes the lockout condition, and the RTC is

again accessible. (Note: activation of external reset, RESETn, does not affect RTC operation.)

18.3.2 Setting Time

The first step in setting the time is to reset the time counters by writing to the RTC Control register.

The user can then set the current year (number of years elapsed since the reference year, 1992) into the upper 8-

bit of the month_year register. Each write to the year register increments the year counter by one.

The month is then set by writing to the lower 8-bit of the month_year register, and each write increments the

month counter by one.

The same procedure should then be used to set the correct day, hour, and minute by writing to the corresponding

registers. Writing to month_year, hour_day, or sec_min register resets the seconds counter to all zeros.

Note that the RTC updates the second counter once per second independent of read or write

operations to RTC registers.

18.3.3 Reading Time

Each 8-bit (upper or lower) of the time interval registers can be independently read. The upper most bit of each 8-

bit section is a Busy Flag, which when set, indicates that a one second clock edge has occurred, and that the time

is being updated in all registers. If the Busy Flag is set when reading any of the time registers, the user must issue

a read to the RTC Control register to clear the Busy Flag, and then re-read all of the time registers until all Busy

Flags are 0.

MFC2000 Datasheet(PDF) 347 Page - List of Unclassifed Manufacturers

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