System Configuration and Protection
MPC561/MPC563 Reference Manual, Rev. 1.2
Freescale Semiconductor
6-43
6.2.2.4.6
Real-Time Clock Register (RTC)
The real-time clock register is a 32-bit read write register. It contains the current value of the real-time
clock. A write to the RTC resets the seconds timer to zero. This register is locked after reset by default.
Unlocking is accomplished by writing 0x55CC AA33 to its associated key register. See
“Keep-Alive Power Registers Lock Mechanism
MSB
0
1
2
3
4
5
6
7
8
9
10
11
12
13
14
LSB
15
Field
RTCIRQ
SEC
ALR
—
4M
SIE
ALE
RTF
RTE
PORESET
0000_0000_000
U
000
U
Addr
0x2F C220
Figure 6-35. Real-Time Clock Status and Control Register (RTCSC)
Table 6-19. RTCSC Bit Descriptions
Bits
Name
Description
0:7
RTCIRQ
Real-time clock interrupt request. Thee bits determine the interrupt priority level of the RTC.
Refer to
Section 6.1.4, “Enhanced Interrupt Controller
” for interrupt level encoding.
8
SEC
Once per second interrupt. This status bit is set every second. It should be cleared by the
software.
9
ALR
Alarm interrupt. This status bit is set when the value of the RTC equals the value programmed in
the alarm register.
10
—
Reserved
11
4M
Real-time clock source
0 RTC assumes that it is driven by 20 MHz to generate the seconds pulse.
1 RTC assumes that it is driven by 4 MHz
12
SIE
Second interrupt enable. If this bit is set, the RTC generates an interrupt when the SEC bit is set.
13
ALE
Alarm interrupt enable. If this bit is set, the RTC generates an interrupt when the ALR bit is set.
14
RTF
Real-time clock freeze. If this bit is set, the RTC stops while FREEZE is asserted.
15
RTE
Real-time clock enable
0 RTC is disabled
1 RTC is enabled
MSB
0
LSB
31
Field
RTC
Reset
Unaffected
Addr
0x2F C224
Figure 6-36. Real-Time Clock Register (RTC)
Summary of Contents for MPC561
Page 84: ...MPC561 MPC563 Reference Manual Rev 1 2 lxxxiv Freescale Semiconductor...
Page 144: ...Signal Descriptions MPC561 MPC563 Reference Manual Rev 1 2 2 46 Freescale Semiconductor...
Page 206: ...Central Processing Unit MPC561 MPC563 Reference Manual Rev 1 2 3 62 Freescale Semiconductor...
Page 302: ...Reset MPC561 MPC563 Reference Manual Rev 1 2 7 14 Freescale Semiconductor...
Page 854: ...Time Processor Unit 3 MPC561 MPC563 Reference Manual Rev 1 2 19 24 Freescale Semiconductor...
Page 968: ...Development Support MPC561 MPC563 Reference Manual Rev 1 2 23 54 Freescale Semiconductor...
Page 1144: ...Internal Memory Map MPC561 MPC563 Reference Manual Rev 1 2 B 34 Freescale Semiconductor...
Page 1212: ...TPU3 ROM Functions MPC561 MPC563 Reference Manual Rev 1 2 D 60 Freescale Semiconductor...
Page 1216: ...Memory Access Timing MPC561 MPC563 Reference Manual Rev 1 2 E 4 Freescale Semiconductor...