FM3164-STR Ramtron, FM3164-STR Datasheet - Page 14

• Manufacturer Part Number: FM3164-STR
• Description: case, leaded, supervisor, reflow, soic, supply, process, max, ram, Interface ICs, package, compatible, voltage, memor...
• Manufacturer: Ramtron

Rev. 2.3
Oct. 2006
01h
/OSCEN
Reserved
CALS
CAL.4-0
00h
CF
CAL
W
R
Reserved
CAL/Control
/Oscillator Enable. When set to 1, the oscillator is halted. When set to 0, the oscillator runs. Disabling the
oscillator can save battery power during storage. On a power-up without battery, this bit is set to 1. Battery-
backed, read/write.
Reserved bits. Do not use. Should remain set to 0.
Calibration sign. Determines if the calibration adjustment is applied as an addition to or as a subtraction from
the time-base. Calibration is explained on page 7. Nonvolatile, read/write.
These five bits control the calibration of the clock. Nonvolatile, read/write.
Flags/Control
Century Overflow Flag. This bit is set to a 1 when the values in the years register overflows from 99 to 00. This
indicates a new century, such as going from 1999 to 2000 or 2099 to 2100. The user should record the new
century information as needed. This bit is cleared to 0 when the Flag register is read. It is read-only for the user.
Battery-backed.
Calibration Mode. When set to 1, the clock enters calibration mode. When CAL is set to 0, the clock operates
normally, and the CAL/PFO pin is controlled by the power fail comparator. Battery-backed, read/write.
Write Time. Setting the W bit to 1 freezes the clock. The user can then write the timekeeping registers with
updated values. Resetting the W bit to 0 causes the contents of the time registers to be transferred to the
timekeeping counters and restarts the clock. Battery-backed, read/write.
Read Time. Setting the R bit to 1 copies a static image of the timekeeping core and place it into the user
registers. The user can then read them without concerns over changing values causing system errors. The R bit
going from 0 to 1 causes the timekeeping capture, so the bit must be returned to 0 prior to reading again.
Battery-backed, read/write.
Reserved bits. Do not use. Should remain set to 0.
Reserved
OSCEN
D7
D7
Reserved
D6
D6
CF
Reserved
CALS
D5
D5
Reserved
CAL.4
D4
D4
Reserved
CAL.3
D3
D3
CAL.2
CAL
D2
D2
CAL.1
D1
D1
FM3104/16/64/256
W
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CAL.0
D0
D0
R