RV-3049 datasheet(28/65 Pages) MICROCRYSTAL

28 / 65 page

Micro Crystal

DTCXO Temperature Compensated Real Time Clock / Calendar Module

RV-3049

28/65

4.3. EEPROM MEMORY ACCESS

The EEPROM Memory has a built-in automatic EEPROM Refresh function, controlled by “EERE” (bit 3 in register

Control_1). If enabled, this function automatically refreshes the content of the EEPROM Memory Pages once an

hour.

The “EEbusy” will be set = “1” (bit 7 in register Control_Status) if the EEPROM Memory Pages are busy due to

write or automatic refresh cycle is in progress. “EEbusy” goes = “0” when writing is finished, EEPROM Memory

Pages shall only be accessed when not busy, i.e. when “EEbusy” = “0”.

A special EEPROM access procedure is required preventing access collision between the internal automatic

EEPROM refresh cycle and external read / write access through interface.

•

Set “EERE” = “0”

Automatic EEPROM Refresh needs to be disabled before EEPROM access.

•

Check for “EEbusy” = “0” Access EEPROM only if not busy

•

Set “EERE” = “1”

It is recommended to enable Automatic EEPROM Refresh at the end of

read / write access

•

Write EEPROM

Allow 10ms wait-time after each written EEPROM register before checking for

EEbusy = “0” to allow internal data transfer

Read access:

Write access:

Disable automatic

EEPROM refresh

Check if EEPROM is busy?

EEPROM read access

EEPROM write access

is permitted

Wait 10ms to allow

internal EEPROM write

Enable automatic

Wait until previous

EEPROM refresh

write cycle is finished

Enable automatic

EEPROM refresh

Note:

A minimum power supply voltage of VPROG = 2.2V is required during the whole EEPROM write procedure; i.e. until

“EEbusy” = “0”.

Clear EERE

EEbusy = 0?

Write EEPROM

Next write?

Set EERE = 1

EEbusy = 0?

Yes

Wait

10ms

Clear EERE

EEbusy = 0?

Read EEPROM

Next read?

Set EERE = 1

Yes

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