14.1.8Block Diagram

The block diagram for the RTC module is shown in Figure 14-1.

LPO

 

Clock

 

 

 

 

ERCLK

 

Source

 

 

Select

 

 

 

 

IRCLK

 

 

 

Background

 

RTCLKS

 

 

 

 

Mode

 

 

 

 

RTCLKS[0]

RTCPS

 

 

 

 

 

Prescaler

RTC

 

Clock

Divide-By

8-Bit Modulo

(RTCMOD)

8-Bit Comparator

8-Bit Counter

(RTCCNT)

VDD

 

D Q

RTIF

E

R

RTIE

Write 1 to

RTIF

RTC

Interrupt

Request

Figure 14-1. Real-Time Counter (RTC) Block Diagram

14.2External Signal Description

The RTC does not include any off-chip signals.

14.3Register Definition

The RTC includes a status and control register, an 8-bit counter register, and an 8-bit modulo register.

Refer to the direct-page register summary in the memory section of this document for the absolute address assignments for all RTC registers.This section refers to registers and control bits only by their names and relative address offsets.

Table 14-1is a summary of RTC registers.

Table 14-1. RTC Register Summary

Name

 

7

6

 

5

4

 

3

2

 

1

0

 

 

 

 

 

 

 

 

 

 

 

 

 

RTCSC

R

RTIF

 

RTCLKS

RTIE

 

 

 

RTCPS

 

 

 

 

 

 

 

W

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

RTCCNT

R

 

 

 

 

RTCCNT

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

W

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

RTCMOD

R

 

 

 

 

RTCMOD

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

W

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

MCF51QE128 MCU Series Reference Manual, Rev. 3

Freescale Semiconductor

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Freescale Semiconductor MCF51QE128RM manual RTC Register Summary, Lpo, Erclk, Irclk, Rtccnt Rtcmod