Real-Time Clock Alarm Register (Rtcal); Real-Time Clock Register (Rtc) - Freescale Semiconductor MPC850 User Manual

Table 10-20. RTCSC Field Descriptions (Continued)
Bits Name
14 RTF Real-time clock freeze enable
0 The real-time clock is unaffected by the FRZ signal.
1 The FRZ signal stops the real-time clock.
15 RTE Real-time clock enable. If set, real-time clock timers are enabled.

10.10.2 Real-Time Clock Register (RTC)

The 32-bit real-time clock register (RTC) contains the current value of the real-time clock.
The maximum value is approximately 136 years. Note that RTC is a keyed register. It must
be unlocked in RTCK before it can be written.
Bit 0 1
Field
Reset
R/W
Addr
Bit 16 17
Field
Reset
R/W
Addr
Table 10-21 describes the RTC.
Bits Name
0–31 RTC Real-time clock. Represents time measured in seconds. Each unit represents one second.

10.10.3 Real-Time Clock Alarm Register (RTCAL)

The real-time clock alarm register (RTCAL) is an alarm reference register. When RTC
increments to the value stored in this register, an alarm interrupt is generated. Note that
RTCAL is a keyed register. It must be unlocked in RTCALK before it can be written.
2 3 4 5
(IMMR & 0xFFFF0000) + 0x224
18 19 20 21
(IMMR & 0xFFFF0000) + 0x226
Figure 10-25. Real-Time Clock Register (RTC)
Table 10-21. RTC Field Description
Chapter 10. System Interface Unit
Description
6 7 8 9
RTC
—
R/W
22 23 24 25
RTC
—
R/W
Description
The Real-Time Clock
10 11 12 13
26 27 28 29
14 15
30 31