VMP2
Configuration
ID 24855, Rev. 02
Page 4 - 20
© 2002 PEP Modular Computers GmbH
4.3.6
Real-time Clock
Access to the 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).
Meanings of abbreviations in Table 4-24
Table 4-22: Register Map RTC M41T56
Address
D7
D6
D5
D4
D3
D2
D1
D0
Function/Range
in BCD Format
0
ST
10 Seconds
Seconds
Seconds / 00-59
1
X
10 Minutes
Minutes
Minutes / 00-59
2
CEB
CB
10 Hours
Hours
Century 0-1/Hour
00-23
3
X
X
X
X
X
Day
Day / 00-07
4
X
X
10 Date
Date
Date / 01-31
5
X
X
X
10
M.
Month
Month / 01-12
6
10 Years
Years
Year / 00-99
7
OUT
FT
S Calibraton
Control
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
necessary to re-initialize the “Seconds” “Minutes” and “Hours” reg-
isters before it will run again.
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