R2023K datasheet(34/50 Pages) RICOH

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R2023K/T

Oscillation adjustment value calculations are exemplified below

(A) For an oscillation frequency = 32768.85Hz and a target frequency = 32768.05Hz

When setting DEV bit to 0:

Oscillation adjustment value = (32768.85 - 32768.05 + 0.1) / (32768.85

× 3.051 × 10-6)

≈ (32768.85 - 32768.05) × 10 + 1

= 9.001

≈ 9

In this instance, write the settings (DEV,F6,F5,F4,F3,F2,F1,F0)=(0,0,0,0,1,0,0,1) in the oscillation adjustment

Thus, an appropriate oscillation adjustment value in the presence of any time count gain represents a

distance from 01h.

When setting DEV bit to 1:

Oscillation adjustment value = (32768.85 - 32768.05 + 0.0333) / (32768.85

× 1.017 × 10-6)

≈ (32768.85 - 32768.05) × 30 + 1

= 25.00

≈ 25

In this instance, write the settings (DEV,F6,F5,F4,F3,F2,F1,F0)=(1,0,0,1,1,0,0,1) in the oscillation adjustment

(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,

DEV=0

DEV=1

Maximum value range

-189.2ppm to 189.2ppm

--62ppm to

63ppm

Minimum resolution

3ppm

1ppm

Notes:

1) Oscillation adjustment circuit 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

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