MCF5253 Reference Manual, Rev. 1
Freescale Semiconductor
26-1
Chapter 26
Real-Time Clock
This chapter provides the external signal descriptions, memory map, register descriptions, and functional
descriptions of the Real-Time Clock module of the MCF5253.
The real time clock (RTC) is a mixed-signal circuit which provides an indicator of time (in seconds) for
various purposes in the system. The RTC does not stop running, even when the rest of the system is
powered down, so long as battery voltage (RTC_VDDA) remains above a certain threshold.
26.1
Block Diagram
is a block diagram of the functional organization of the RTC block.
Figure 26-1. Real Time Clock Block Diagram
26.2
External Signal Description
describes the RTC external signals.
26.3
Memory Map and Register Definitions
The RTC module’s register is accessible via the USB, ATA DMA, and clock integration module memory
space. An RTC control and an RTC status bit are also included in the miscellaneous configuration register.
Table 26-1. RTC Signals
Signal Name
Abbreviation
Function
I/O
RTC Crystal In
RTC_CRIN
32.768 kHz crystal input clock.
I
RTC Crystal Out
RTCCROUT 32.768 kHz crystal output.
O
RTC Supply Voltage
RTC_VDDA Battery supply to RTC
–
RTC Ground
RTCVSSA
Ground for RTC supply
–
RTC Logic
RTC_TIME
1pps
32.768 kHz
RTC_CRIN
RTCCROUT
RTC_VDDA
RTCVSSA
RTC Power Loss Status
RTC Power Loss Clear
To/From ATA-DMA
Config Register
Oscillator
in ATA-DMA
Summary of Contents for MCF5253
Page 1: ...Document Number MCF5253RM Rev 1 08 2008 MCF5253 Reference Manual...
Page 26: ...MCF5253 Reference Manual Rev 1 xxvi Freescale Semiconductor...
Page 32: ...MCF5253 Reference Manual Rev 1 xxxii Freescale Semiconductor...
Page 46: ...MCF5253 Introduction MCF5253 Reference Manual Rev 1 1 14 Freescale Semiconductor...
Page 62: ...Signal Description MCF5253 Reference Manual Rev 1 2 16 Freescale Semiconductor...
Page 98: ...Instruction Cache MCF5253 Reference Manual Rev 1 5 10 Freescale Semiconductor...
Page 104: ...Static RAM SRAM MCF5253 Reference Manual Rev 1 6 6 Freescale Semiconductor...
Page 128: ...Synchronous DRAM Controller Module MCF5253 Reference Manual Rev 1 7 24 Freescale Semiconductor...
Page 144: ...Bus Operation MCF5253 Reference Manual Rev 1 8 16 Freescale Semiconductor...
Page 176: ...System Integration Module SIM MCF5253 Reference Manual Rev 1 9 32 Freescale Semiconductor...
Page 198: ...Analog to Digital Converter ADC MCF5253 Reference Manual Rev 1 12 6 Freescale Semiconductor...
Page 246: ...DMA Controller MCF5253 Reference Manual Rev 1 14 18 Freescale Semiconductor...
Page 282: ...UART Modules MCF5253 Reference Manual Rev 1 15 36 Freescale Semiconductor...
Page 344: ...Audio Interface Module AIM MCF5253 Reference Manual Rev 1 17 46 Freescale Semiconductor...
Page 362: ...I2 C Modules MCF5253 Reference Manual Rev 1 18 18 Freescale Semiconductor...
Page 370: ...Boot ROM MCF5253 Reference Manual Rev 1 19 8 Freescale Semiconductor...