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RICOH imagine. change.

RICOH ELECTRONIC DEVICES CO., LTD.

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Glossary

Time keeping current It means the consumption current which operates only clock and calendar without accessing CPU.
Time keeping voltage It means the voltage which operates only clock and calendar without accessing CPU.
The operating voltage to access CPU is specified in the other specification.
Alarm function It means the function which outputs the interrupt signal at the setting time.
Periodic interrupt function It means the interrupt function which outputs at constant periodic such as every seconds, every minutes, every hours and 1 month.
It is useful when indicating clock and calendar by using the RTC clock data.
32kHz clock output It is possible to output same clocks of crystal frequency which is used in RTC. There are four types of selectable outputs such as Open drain controllable by pin, Open drain keeping output enable, CMOS controllable by pin, CMOS with level shifter. It is suitable for CPU sub-clock.
The clock adjustment circuit It means the circuit which adjusts time gain or loss by the software. It is useful to compensate the crystal frequency deviation.
The OSC halt sensing circuit The circuit records past oscillation halt to internal register.
It can be used to judge the validity of internal data in such events as power-on.
Battery checker It records them as Flag when detecting voltage threshold of backup battery.
It is useful as checker of the output voltage for backup battery.
32768Hz/32000Hz
crystal selectable
RTC generally use 32768Hz crystal oscillator. But RS5C372A/B can select 32000Hz crystal oscillator as well as 32768Hz crystal oscillator. 32KOUT pin outputs 32000Hz clock pulses when 32000Hz crystal oscillator is used.
Battery back-up
switch-over function
R2051x, R2061x, R2062 and R2262 incorporate the automatic switch-over circuit which can switch between a main power supply and a back-up battery. Primary battery, Secondary battery, Electric double layered capacitor or Aluminum electrolytic capacitor are selectable as backup battery in R2051x and R2061x. Secondary battery, Electric double layered capacitor or Aluminum electrolytic capacitor are selectable as backup battery in R2062 and R2262. R2262 includes VR charger.
Frequency Deviation
(0±5ppm)
R2025S/D and R2045S/D incorporates 32768Hz crystal unit. The oscillation frequency is adjusted to high precision.(0±5ppm:at 25°C)
The deviation corresponds to ±13 seconds per every month.
By using the clock adjustment circuit, time deviation also can be calibrated to 3 or 6 or 9±5ppm.
ECO mode In the case that equivalent series resistance of crystal oscillator is low,(approximately equal or less than 45kΩ) time keeping current can be reduced, if ECO mode is active. There are a register setting type such as R2223x, and a pin setting type such as R2221x in the setting ECO mode.