Sparkfun RV-8803 Technical document

Real Time Clock Module - RV-8803 (Qwiic) Hookup Guide

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Introduction

The Real Time Clock Module - RV-8803 (Qwiic) is a Qwiic-enabled breakout board for the RV-8803 RTC module. The RV-8803 boasts some impressive

features including a temperature compensated crystal, extremely precise time-keeping, low power consumption, time stamp event input along with a

user-programmable timing offset value. It even has a programmable Clock Output to control precise timing for peripheral devices. The RV-8803 also has

an improved I C interface compared to the RV-1805 RTC that removes the need to sequence commands/writes to the device. This is particularly helpful if

you are not using our Arduino Library to control the RTC.

SparkFun Real Time Clock Module - RV-8803 (Qwiic)

 BOB-16281

In this hookup guide we will go over the unique features of the RV-8803 along with some Arduino examples demonstrating how to use those features. By

the end of this tutorial you will have your Real Time Clock Module - RV-8803 (Qwiic) configured and tick-tocking away (well, ticking, maybe not tocking)

for your next time-keeping project!

Required Materials

To follow along with this guide you will need a microcontroller to configure and communicate with the RTC Module breakout. Below are a few options that

come Qwiic-enabled out of the box:

Product Showcase: SparkFun Qwiic Real Time Clock ModuleProduct Showcase: SparkFun Qwiic Real Time Clock Module

SparkFun Qwiic Pro Micro - USB-C (ATmega32U4) SparkFun Thing Plus - ESP32 WROOM

If your chosen microcontroller is not already Qwiic-enabled, you can add that functionality with one or more of the following items:
 DEV-15795  WRL-15663
SparkFun RedBoard Qwiic
 DEV-15123
SparkFun RedBoard Artemis
 DEV-15444
SparkFun Qwiic Cable Kit
 KIT-15081
SparkFun Qwiic Shield for Arduino
 DEV-14352

You will also want at least one Qwiic cable to connect your RTC to your microcontroller.
SparkFun Qwiic Adapter
 DEV-14495
SparkFun Qwiic Shield for Arduino Nano
 DEV-16130
Qwiic Cable - 100mm
 PRT-14427
Qwiic Cable - 200mm
 PRT-14428
Qwiic Cable - 50mm
 PRT-14426
Qwiic Cable - 500mm
 PRT-14429

Some of the examples demonstrate how to use more than just the I C pins. If you want to follow along with them you will need to solder to the EVI, INT,

CLKOUT and CLKOE pins broken out on the board. Click the button below to see some recommended soldering tools and materials if you need them.

ADDITIONAL TOOLS FOR SOLDERING TO THE REAL TIME CLOCK MODULE RV-8803 BREAKOUT

Finally, if you want to fine tune the RV-8803's oscillator for extremely precise time keeping you will need to use an oscilloscope or logic analyzer to

calibrate it. Click the button below to see some options for oscilloscopes and logic analyzers if you need one.

ADDITIONAL TOOLS FOR CALIBRATING THE REAL TIME CLOCK MODULE RV-8803 BREAKOUT

Suggested Reading

If you aren't familiar with the Qwiic system, we recommend reading here for an overview:

Qwiic Connect System

We also recommend taking a look at the hookup guides for the Qwiic Shields listed above if you plan on using one of them. Brushing up on your skills in

I C is also recommended as all Qwiic sensors communicate via I C.

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I2C

An introduction to I2C, one of the main embedded communications

protocols in use today.

Qwiic Shield for Arduino & Photon Hookup Guide

Get started with our Qwiic ecosystem with the Qwiic shield for Arduino or

Photon.

Hardware Overview

The heart of this breakout is the RV-8803 Real Time Clock module from Micro Crystal. In this section we'll cover most of the features and characteristics

of the RV-8803 and this breakout but if you are looking for a more thorough synopsis of the RV-8803, take a look through the Application Manual . The

table below lists some of the operating characteristics of the RV-8803.

Characteristic Value

Operating Voltage Range 1.5V - 5.5V

Time Accuracy (Temp. Compensated -40° to +85°C) +/-3 ppm

Time Accuracy (Temp. Compensated +85° to +105°C) +/-7 ppm

Current Consumption 240 nA (Typ.) to 350 nA

I C Address 0x64

Power

There are two primary ways to power the SparkFun Real Time Clock Module - RV-8803 (Qwiic). The best and easiest way is through the Qwiic

Connectors on either side of the board. When used with any of our Qwiic-enabled boards or our Qwiic Shields, this voltage will be 3.3V. The other power

input is the 3.3V pin broken out. The board also includes a 3V 47mAh battery in the 12mm coin cell battery holder on the back for backup power.

SparkFun Qwiic Shield for Arduino Nano Hookup Guide

Hookup Guide for the SparkFun Qwiic Shield for Arduino Nano.

SparkFun Qwiic Shield for Thing Plus Hookup Guide

A short guide for assembling and using the SparkFun Qwiic Shield for

Thing Plus.

Heads up! While the RV-8803 can accept an input voltage between 1.5-5.5V, the Qwiic system operates at 3.3V so it is recommended to power

the RTC with 3.3V or lower, especially if you are using it with other Qwiic devices.

Qwiic and I C Interface

The easiest way to use the Real Time Clock Module - RV-8803 (Qwiic) is with the Qwiic connect system. Just connect the board using a Qwiic Cable to

your microcontroller to start talking to it. Alternatively, you can solder to the I C pins broken out on the board. The 7-bit I C unshifted address is 0x32

(0110010b). This is a hardware set address and there are no alternate slave addresses for the RV-8803. If you need multiple RTC's on a single I C bus

you will need to use a multiplexer or mux like the Qwiic Mux Breakout - 8 Channel.

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Pin Descriptions

While the Qwiic interface is the easiest and fastest way to start using your RTC, there are several other pins for extra functionality broken out. You will

need to either solder to these pins to make use of them or you can create a temporary connection using something like these IC Hooks. The table below

outlines all of the pins broken out on the RTC and summarizes their functionality.

Label

Function

Input/Output Functionality Notes

GND Ground Input 0V/Common Voltage

3.3V Power

Supply

Input Power Supply voltage range is 1.5-3.3V

SDA I C Data

Signal

Bi-directional Bi-directional data line. Voltage should not exceed power supply (e.g. 3.3V).

SCL I C Clock

Signal

Input Master-controlled clock signal. Voltage should not exceed power supply (e.g. 3.3V).

EVI Event

Input

Input/Output External event interrupt pin with Time Stamp Function. Active LOW by default. Tied to the button labeled EVI

for easy use.

INT Interrupt

Output

Output Open-drain, active LOW. Used to output Alarm, Periodic Countdown Timer, Periodic Time Update and

External Event Interrupt signals. Pulled to 3.3V with 100k resistor.

CLKOUT Clock

Output

Output Programmable square wave output for peripheral devices. Available frequencies are 32.768 kHz (default),

1024 Hz or 1Hz. Set on power-up and controlled by the state of CLKOE pin. When disabled, pin is high

impedance.

CLKOE Clock

Output

Enable

Input Enables and disables the CLKOUT pin. If HIGH, CLKOUT is enabled and is in output mode. If LOW,

CLKOUT is disabled. Pin is pulled to GND by default with a 100k resistor.

The EVI pin is broken out but also connected to the button highlighted to easily trigger interrupt events like time stamps.

Jumpers

There are two jumpers on the SparkFun Real Time Clock Module - RV-8803 (Qwiic) labeled "I C" and "LED". The I C jumper is closed by default and can

be opened by severing the trace between the three pads to disconnect the two 4.7k Ohm resistors from the SDA and SCL lines. Open this jumper for if

you have many I C devices on the same bus or to reduce current draw for low-power projects. The LED jumper is closed by default and enables the on

board power LED. To open it, simply sever the trace in between the two jumper pads to disconnect the power LED (particularly useful for low-power

applications). Note: The power LED is tied to the 3.3V input and is not powered by the backup battery.

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I C Jumper highlighted LED Jumper Highlighted

Never worked with solder jumpers before or need some tips? Take a look at our How to Work with Jumper Pads and PCB Traces Tutorial.

Board Dimensions

The SparkFun Real Time Clock Module - RV-8803 (Qwiic) is built to the standard 1 x 1" size for Qwiic Breakouts. One thing you may notice is this board's

lack of mounting holes. In order to fit the 1 x 1" standard for Qwiic Breakouts, there was no space for mounting holes as the battery holder takes the

space normally reserved for those mounting holes.

Hardware Assembly