rs5c338a RICOH Co.,Ltd., rs5c338a Datasheet - Page 28

• Manufacturer Part Number: rs5c338a
• Description: 3-wire Serial Interface Real-time Clock Ics With Voltage Monitoring Function
• Manufacturer: RICOH Co.,Ltd.

28
R
2.2 Measurement of Oscillation Frequency
2.3 Adjustment of Oscillation Frequency
The oscillation frequency of the oscillation circuit can be adjusted by varying procedures depending on the usage of
the R
flow chart below serves as a guide to selecting an optimum oscillation frequency adjustment procedure for the
relevant system.
*
*
*
×
*
*
*
1) The R
2) A frequency counter with 6 (more preferably 7) or more digits on the order of 1ppm is recommended for use in the measurement of the oscillation fre-
3) The CLKC input should be connected to the V
1) Generally, crystal oscillators for commercial use are classified in terms of their center frequency depending on their load capacitance (C
2) Basically, the R
3) Time count precision as referred to in the above flow chart is applicable to normal temperature and actually affected by the temperature characteristics
5C338A
to 1 in the control register 2.
quency of the oscillation circuit.
×
divided into ranks on the order of ±10, ± 20, and ±50 ppm depending on the degree of their oscillation frequency variations.
and other properties of crystal oscillators.
5C338A in the system into which they are to be built and on the allowable degree of time count errors. The
×
5C338A are configured to generate 32.768-kHz clock pulses for output from the 32KOUT pin at power-on conditionally on setting the XSTP bit
Use 32-kHz clock circuit without regard
to its frequency precision?
Allowable time count precision is on order of oscillation
frequency variations of crystal oscillator *
frequency variations of real-time clock? *
clock circuit?
R
Use 32-kHz
OSCOUT
×
32KOUT
5C338A
OSCIN
Start
CLKC
×
VDD
V
5C338A are configured to cause frequency variations on the order of ±5 to ±10ppm at normal temperature.
SS
YES
NO
NO
32.768kHz
Allowable time count precision is on order of oscillation
frequency variations of crystal oscillator *
frequency variations of real-time clock? *
DD
pin with a pull-up resistor.
2,
1
plus
*
3
Frequency
counter
YES
YES
NO
2,
1
*
plus
3
NO
YES
To Course (A)
To Course (B)
To Course (C)
To Course (D)
L
) and further