R2043K Datasheet, PDF (32/48 Pages) RICOH electronics devices division – 4-wire Serial Interface

R2043K/T
Oscillation adjustment value = (32768.85 - 32768.05 + 0.0333) / (32768.85 × 1.017 × 10^-6)
≈ (32768.85 - 32768.05) × 30 + 1
= 23.51 ≈ 24
In this instance, write the settings (DEV,F6,F5,F4,F3,F2,F1,F0)=(1,0,0,1,1,0,0,0) in the oscillation adjustment
register.
(B) For an oscillation frequency = 32762.22Hz and a target frequency = 32768.05Hz
When setting DEV bit to 0:
Oscillation adjustment value = (32762.22 - 32768.05) / (32762.22 × 3.051 × 10^-6)
≈ (32762.22 - 32768.05) × 10
= -58.325 ≈ -58
To represent an oscillation adjustment value of - 58 in 7-bit coded decimal notation, subtract 58 (3Ah) from 128
(80h) to obtain 46h. In this instance, write the settings of (DEV,F6,F5,F4,F3,F2,F1,F0) = (0,1,0,0,0,1,1,0) in the
oscillation adjustment register. Thus, an appropriate oscillation adjustment value in the presence of any time
count loss represents a distance from 80h.
When setting DEV bit to 1:
Oscillation adjustment value = (32762.22 - 32768.05) / (32762.22 × 1.017 × 10^-6)
≈ (32762.22 - 32768.05) × 30
= -174.97 ≈ -175
Oscillation adjustment value can be set from -62 to 63. Then, in this case, Oscillation adjustment value is out of
range.
(4) Difference between DEV=0 and DEV=1
Difference between DEV=0 and DEV=1 is following,
Maximum value range
Minimum resolution
DEV=0
-189.2ppm to 189.2ppm
3ppm
DEV=1
--62ppm to 63ppm
1ppm
Notes:
1) Oscillation adjustment does not affect the frequency of 32.768-kHz clock pulses output from the
32KOUT pin.
2) If following 3 conditions are completed, actual clock adjustment value could be different from target
adjustment value that set by oscillator adjustment function.
1. Using oscillator adjustment function
2. Access to R2043K/T at random, or synchronized with external clock that has no relation to R2043K/T,
or synchronized with periodic interrupt in pulse mode.
3. Access to R2043K/T more than 2 times per each second on average.
For more details, please contact to Ricoh.
How to evaluate the clock gain or loss
The oscillator adjustment circuit is configured to change time counts of 1 second on the basis of the settings of
the oscillation adjustment register once in 20 seconds or 60 seconds. The oscillation adjustment circuit does
not effect the frequency of 32768Hz-clock pulse output from the 32KOUT pin. Therefore, after writing the
oscillation adjustment register, we cannot measure the clock error with probing 32KOUT clock pulses. The way
to measure the clock error as follows:
(1) Output a 1Hz clock pulse of Pulse Mode with interrupt pin
Set (0,0,x,x,0,0,1,1) to Control Register 1 at address Eh.
(2) After setting the oscillation adjustment register, 1Hz clock period changes every 20seconds ( or every 60
seconds) like next page figure.
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Rev.2.06
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