
Section 9



Real-Time Clock




Caution:
!
The standard
A supercapacitor on the PmPPC7448 provides backup operation in the event of a power failure. However, if power is not reapplied within 12 hours, all data stored in
BLOCK DIAGRAM
Figure 9-1: M41T00 Real-Time Clock Block Diagram
OSC1 | Oscillator | Divider | 1Hz | |
| Seconds | |||
OSC0 | 32.768 KHz |
|
| |
|
|
| ||
FT/OUT |
|
| Minutes | |
|
|
| ||
VCC | Voltage |
| Century/Hours | |
Control |
| |||
VSS | Sense and |
| ||
Logic | Day | |||
Switch | ||||
VBAT | Circuitry |
|
| |
|
|
| Date | |
|
|
| Month | |
SCL | Serial |
|
| |
Bus |
| Year | ||
|
| |||
| Interface |
| ||
SDA |
|
| ||
| Address |
| ||
|
|
| ||
|
| Register | Control |
OPERATION
The M41T00 clock operates as a slave device on the serial bus. To obtain access, the RTC implements a start condition followed by the correct slave address (D0h). Access the eight bytes in the following order:
PmPPC7448 User’s Manual |