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CP321
4.4.4
Real-time Clock
Access to the real-time clock (RTC) is effected via the I2C bus. The RTC uses address 0xD0.
For more detailed information please refer to the manuals for the ST - Microelectronics M41T56
and the Motorola MPC 8245 (I2C - Bus).
Table 4-22:Register Map RTC M41T56
REG.
BYTE
D7
D6
0
ST
1
X
2
CEB
CB
3
X
X
4
X
X
5
X
X
6
10 Years
7
OUT
FT
Legend for Table 4-22:
CEB = Century enable bit
CB = Century bit
FT = Frequency test bit
OUT = Output level
ST = Stop bit
S = Sign bit
Note...
When the RTC has once been stopped due to low voltage, it is neces-
sary to re-initialize the "Seconds" "Minutes" and "Hours" registers
before it will run again.
ID 24977, Rev. 02
ADDRESS BITS
D5
D4
D3
10 Seconds
10 Minutes
10 Hours
X
X
X
10 Date
X
10M.
S
© 2003 Kontron Modular Computers GmbH
D2
D1
D0
Seconds
Minutes
Hours
Day
Date
Month
Years
Calibraton
Configuration
FUNCTION RANGE IN
BCD FORMAT
Seconds: 00 - 59
Minutes: 00 - 59
Century:
0 - 1
Hours:
00 - 23
Day: 00 - 07
Date: 01 - 31
Month: 01 - 12
Year: 00 - 99
Control
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