PSoC5LP Lab 09: I2C RTC Module

Objective

Overview

A Real-Time Clock (RTC) module in an embedded system is a dedicated hardware component that accurately tracks time, often across various power cycles. It provides precise timekeeping regarding seconds, minutes, hours, days, months, and years. RTCs are crucial for applications requiring accurate time management, such as data logging, scheduling tasks, alarms, and managing timestamps in file systems.

Key Features and Functions of RTC Modules

1. Time and Date Tracking: An RTC maintains accurate time and date information. It can manage leap years, handle month-end adjustments, and keep track of hours, minutes, seconds, day of the week, and year.
2. Battery Backup: RTCs typically operate with a low-power backup battery. This feature allows them to continue counting time even when the main power supply is off, ensuring uninterrupted time tracking.
3. Low Power Consumption: Most RTC modules consume minimal power, making them ideal for battery-powered devices that require continuous timekeeping, such as wearable devices, portable equipment, and IoT nodes.
4. Programmable Alarms and Interrupts: Many RTCs include alarm and interrupt features. Programmable alarms can trigger at specified times or intervals, which is useful for scheduling tasks in low-power modes or waking up the system from sleep.
5. I2C or SPI Interface: RTCs commonly use I2C or SPI communication protocols to interface with microcontrollers, allowing simple, reliable integration into embedded systems.
6. Automatic Calibration: Some advanced RTCs have self-calibration mechanisms to maintain high accuracy. This feature can correct for drift caused by temperature variations or oscillator aging.
7. Applications: RTC modules are essential in applications where maintaining accurate time is critical, including:
   • Data logging (e.g., environmental monitoring)
   • Scheduled tasks and automation
   • Timestamping in file systems
   • Alarm systems and reminders
   • Low-power devices where periodic wake-ups are necessary

Popular RTC Modules

• DS1307: A widely-used I2C-based RTC with battery backup and basic date/time tracking, suitable for simple applications.
• DS3231: Known for high accuracy, this I2C RTC has an integrated temperature-compensated crystal oscillator (TCXO) and features alarms, making it ideal for precision applications.
• PCF8563: This low-power RTC also uses I2C and is known for its power efficiency, making it popular in portable devices.

In summary, RTC modules in embedded systems enable precise and reliable timekeeping across power cycles, essential for any application requiring accurate time information or scheduled operations. Their low-power design and integration flexibility make them a core component in modern embedded and IoT systems.

Required Reading Material

• Lesson KB 01: Create a PSoC Project using PSoC Creator
• Datasheets:
  • DS3231 Real-Time Clock module
  • DS1307 Real-Time Clock module
• PSoC Creator Components
  • I2C Master/Multi-Master/Slave
  • CharLCD

Required Components

If you use the Cypress CY8CKIT-059 Kit, the onboard LED and button will be used in this lab.

The following components are required for this lab.

	DS3231 (or DS1307) RTC module	x 1
	Character LCD Module	x 1
	Red LED (or onboard LED)	x 1

Circuit / Schematic

Procedure