Revision as of 12:21, 5 June 2015

Objective

In this tutorial we will be discussing about the internal RTC of LPC1768. We will see what are the different registers associated with the RTC but we will mainly focus on basics registers required to use RTC. Later we will see how to use Explore Embedded library for RTC.

RTC Registers

RTC Register Configuration

CCR ( Clock Control Register )

Bit 0 – CLKEN : Clock Enable
This bit is written with one to enable time counters and written with zero to disable time counters.

Bit 1 - CTCRST : CTC Reset

Bit 3:2
These bits must be set to zero for normal RTC operation.

Bit 4 - CCALEN : Calibration counter enable
To disable calibration counter and reset it to zero, write one to this bit. When written zero, the counter is enabled and starts counting

Bit 31:5 Reserved

Time Counter Register

The time value consists of the eight counters and there is one register associated with each counter. To update the RTC, new values should be written to these registers.

Consolidated Time Registers

The values of the Time Counters can optionally be read in a consolidated format which allows the programmer to read all time counters with only three read operations.

There are 3 Consolidated Time Registers. The minimum and maximum values of the various fields in these registers are same as the respective Time Counter Register.

These registers are read only. New values should be written to Time Counter Registers.

Consolidated Time Register 0 (CTIME0)

Consolidated Time Register 1 (CTIME1)

Consolidated Time Register 2 (CTIME2)

Steps for Configuring RTC

Code EXample

Example 1

Using Explore Embedded Liberaries