RV-3029 Datasheet, PDF (28/67 Pages) MICORO CRYSTAL SWITZERLAND – DTCXO Temperature Compensated Real Time Clock

Micro Crystal
DTCXO Temperature Compensated Real Time Clock / Calendar Module
RV-3029
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:
Clear EERE
Disable automatic
EEPROM refresh
Clear EERE
Disable automatic
EEPROM refresh
No
EEbusy = 0?
Yes
Read EEPROM
Check if EEPROM is busy?
EEPROM read access
is permitted
No
EEbusy = 0?
Yes
Write EEPROM
Check if EEPROM is busy?
EEPROM write access
is permitted
Yes
Next read?
No
Set EERE = 1
Enable automatic
EEPROM refresh
Wait
10ms
Wait 10ms to allow
internal EEPROM write
No
EEbusy = 0?
Yes
Yes
Next write?
No
Set EERE = 1
Wait until previous
write cycle is finished
Enable automatic
EEPROM refresh
Note:
A minimum power supply voltage of V_PROG = 2.2V is required during the whole EEPROM write procedure; i.e. until
“EEbusy” = “0”.
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