M4T32-BR12SHX STMICROELECTRONICS [STMicroelectronics], M4T32-BR12SHX Datasheet - Page 26

• Manufacturer Part Number: M4T32-BR12SHX
• Description: Serial real-time clock with 44 bytes NVRAM and reset
• Manufacturer: STMICROELECTRONICS [STMicroelectronics]

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Figure 14. Crystal accuracy across temperature
Figure 15. Calibration waveform
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.
NORMAL
POSITIVE
CALIBRATION
NEGATIVE
CALIBRATION
Frequency (ppm)
–100
–120
–140
–160
–20
–40
–60
–80
20
0
–40
–30
–20
–10
0
10
Temperature C
T
K = –0.036 ppm/ C
F
F = K x (T –T
O
= 25 C ± 5 C
20
30
O
)
2
40
2
± 0.006 ppm/ C
50
60
2
70
80
AI00999b
AI00594B