Maxim Integrated MAX31343SHLD# Real Time Clock - Review

Table of contents

RoadTest: Maxim Integrated MAX31343SHLD# Real Time Clock

Author: misaz

Creation date:

Evaluation Type: Development Boards & Tools

Did you receive all parts the manufacturer stated would be included in the package?: True

What other parts do you consider comparable to this product?: DS3231 and some other RTC chips with publicly availaible documentation.

What were the biggest problems encountered?:

Detailed Review:



I welcome you to reading my review about Maxim Integrated MAX31343 evaluation shield. Shield is used for evaluating MAX31343 Real Time Clock (RTC) chip from Maxim Integrated. As part of shield there is connector for MAX32625PICO board which is bundled with shield. This board is used for evaluating features of RTC chip without need for any external programming using provided software. In this review I point multiple aspects about shield, RTC chip, microcontroller on PICO board, available development environment, available software, documentation, and some other aspects. This review is separated to multiple blog post presented in following table of contents. There are three kinds of article – tutorial, project, and review. Tutorial is written as detailed step by step tutorial which show how to use this Shield and RTC chip in some way. Projects show and describe projects which I have done for testing purposes. Review chapters describe aspects of board and contains my thoughts about this board and related parts.


In this article you can find introduction (which you are reading now), overview of review and project chapters (which is below), summary (which is below) and score (which is in top left corner above to this text).


Table of Contents



Overview of Table of Contents

The main chapters of review start with text “Review” in name. There are 3 these chapters. First of them is chapter “Review of RTC chip” and focus on MAX31343 chip. Second chapter “Review of Evaluation Shield” describes evaluation shield itself and finally third chapter “Review of MAX32625 Microcontroller and MAX32625PICO board” describes in detail bundled PICO board and it’s MCU. Following image highlights parts that are covered by chapters of my review.




As part of review I provided one tutorial showing how to simply use this shield with Arduino Uno and provided library by Maxim. When preparing this tutorial, I used 3.3V chip powering and 5V signalling level at the time because Arduino UNO is 5V naturally. Following photo show MAX31343 Shield connected to my Arduino as presented in tutorial:




When evaluating I have done 3 projects. First project is my own MAX31343 Library. For review purpose I wanted to experience with chip at low level to gain experiences with features that it offers, so I decided to write my own library. Project chapter describe my library briefly and library is available at github. When developing library I was using shield connected to STM32L552 chip on STM NUCLEO board and to Cypress PSoC 62 on PSoC® 62S2 Wi-Fi BT Pioneer Kit (which I was roadtesting in my previous review). Both boards have Arduino UNO compatible connector so connecting shield was easy. These boards I evaluated with different powering options used. I also tested 1.8V interface logic because both boards support it and shield also support this low voltage. Following photos show evaluated shield on NUCLEO board with STM32L552 MCU:




Following photo shows evaluated shield on Cypress PSoC 62 on PSoC® 62S2 Wi-Fi BT Pioneer Kit.




My last project was Linux driver which I have developed on Raspberry Pi. Raspberry Pi has no Arduino UNO compatible connecter, but it is easy to connect shield to Rasbberry Pi using wires.



To summarize I used 4 different platforms ranging from 8-bit MCU to 64-bit SBC when doing projects and experimenting with shield and MAX31343 chip. In all cases shield and chip worked well.


I recommend reading all three review chapters as listed in table of contents and if you are interested in it furthermore, you can read tutorial or my articles about my testing projects.


Following table contains summary and extraction from my detailed chapters. Below it is score which I give to reviewed parts.



MAX31343SHLD is nice shield evaluating very good RTC chip with very good performance. Evaluation shield is designed in very flexible way allowing you use this RTC chip in almost any configuration. Concept of allowing evaluating chips using GUI software and USB-to-I2C bridge provided by PICO board is good and I like it very much. Only disadvantage should be price which I consider high even when considered that shield is evaluating high-end RTC chip and there are some expensive components like supercapacitor.





MAX31343 RTC Chip
  • Integrated crystal reducing need to provide external one
  • Accuracy
  • Trickle charger
  • Temperature sensor
  • Double buffered date and time registers
  • Support for years 2000-2199 instead of still common 1900-2099
  • Extremely small footprint
  • Wide input powering range
  • No hobby friendly (hand-solderable) package variant available
  • Only two alarms and Alarm 2 is different than Alarm 1
  • Price
Evaluation Shield
  • Fully assembled (really no soldering or other mechanical operations needed)
  • Test points for every signal and power supply (easy oscilloscope/logic analyser connection)
  • Voltage level converters on each signal allowing set chip Vcc differently on logic signal levels
  • Jumpers for disconnecting any signal
  • Possibility to evaluate all powering modes and power sources
  • Supercapacitor
  • Pin description only from bottom side
  • IOREF vs 1V8
  • No possibility to use Arduino and PICO board at the same time
  • Price
MAX32625PICO Board
  • Size
  • PMIC
  • Flexibility
  • Onboard peripherals
  • Price
  • Support for both 3.3 and 1.8V
  • Hard to press button near to USB connector
  • Complicated design
  • Hard to program
MAX32625 MCU
  • Footprint Size
  • Support for two IO voltage levels
  • HW accelerated 1-Wire peripheral
  • Pulse Train Engine
  • Simple firmware development
  • MBED support
  • Strict powering requirements
  • Price
  • MAX31343 GUI tool works out of box
  • Software supports all chip features
  • High quality Arduino Library provided
  • MAX32625 SDK is good quality and easy to understand
  • Good code examples in Arduino Library
  • Good code examples as part of MAX32625PeriphDriver library
  • GUI tool not available for Linux
  • Hard to find Eclipse IDE for MAX32625 on website
  • Mainline OpenOCD does not work for MAX32625
  • Bundled OpenOCD works only with DAP-Link and FTDI probes
  • MAX31343 (RTC) datasheet is good
  • MAX32625PICO datasheet is good
  • MAX14750 (PMIC) datasheet is good
  • MAX32625 (MCU) datasheet is good
  • Undescribed purpose of having need for two footprints
  • MAX32625 (MCU) UG has no graphical visualization of registers structure
  • MAX32625 (MCU)UG lacks important information
  • Documentation visual and structural inconsistency
  • Schematics available in datasheets only on separated 90deg rotated pages
  • PICO schematic is hard to understand
  • Availability at distributors


RoadTest Score


Product Performed to Expectations is calculated as sum of following fields from previous table: RTC Chip (weight 0,4), Shield (weight 0,4) and Software (weight 0,2) = 0.92 => 9/10


Specifications were sufficient to design with I give 9/10 because RTC Chip and Shield documentation was quite good while MAX32625 documentation is quite bad. Because main topic of review is MAX31343 and shield I won’t affect rating by MAX32625 performance very much.


Demo Software was of good quality I give 10/10 because GUI evaluation tool, all demos for Arduino Library and demos of MAX32625 SDK were very good.


Product was easy to use I give 10/10 because everything related to MAX31343 and evaluation shield worked out of box and was easy to use. I do not include MAX32625 related notes like OpenOCD troubles and need for soldering JTAG wires to this score because this is not main topic of this review.


Support materials were available I give 6/10 mainly because of overall documentation inconsistency which apply to almost all documents from Maxim. While documentation related to MAX31343 and shield is quite good and I had only minor notes about that, documentation related to MAX32625 is bad. But because MAX32625 is not main topic of review I won’t decrease rating so much.


The price to performance ratio was good I give 6/10 because shield is significantly overpriced even it features high-end peripherals.