Clock operations

M41T94

26/41

Figure 14.

Crystal accuracy across temperature

Figure 15.

Calibration waveform

4.9

Century bit

Bits D7 and D6 of clock register 03h contain the CENTURY ENABLE bit (CEB) and the

CENTURY bit (CB). Setting CEB to a '1' will cause CB to toggle, either from a '0' to '1' or

from '1' to '0' at the turn of the century (depending upon its initial state). If CEB is set to a '0,'

CB will not toggle.

AI00999b

–160

0

10203040506070

Frequency (ppm)

Temperature

°C

80

–10

–20

–30

–40

–100

–120

–140

–40

–60

–80

20

0

–20

ΔF

2

K = –0.036 ppm/

F

AI00594B

NORMAL

POSITIVE

CALIBRATION

NEGATIVE

CALIBRATION