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PPG Overview

This module demonstrates photoplethysmography (PPG) sensing using the Renesas DA14531 Pro Development Kit and the Maxim Integrated MAX86141 optical sensor.

The example is designed for the KuoQuo Pivot smart ring proof-of-concept platform and provides:

  • MAX86141 initialization
  • LED configuration
  • PPG sample acquisition
  • FIFO support
  • Interrupt-driven sampling
  • Motion-aware biometric sensing
  • Optional BLE GATT service integration

The same hardware setup supports two firmware variants:

Firmware Variant Description
Basic Simple MAX86141 communication and sensor validation
Basic + BLE Real-time PPG streaming over Bluetooth LE

Prerequisites

Before starting this example, it is recommended that you have successfully completed the DA14531 Blinky Peripheral Example (Renesas Official Guide)

This ensures:

  • SDK environment is properly configured
  • Keil setup is working correctly
  • Flashing and debugging are functional
  • UART and GPIO configuration are verified

Additional Reference (PPG Sensor)

For MAX86141-based development, it is recommended to review the MAX86140EVSYS Datasheet (Analog Devices / Maxim Integrated)

This helps ensure:

  • Proper understanding of optical PPG operation
  • LED timing and current configuration awareness
  • FIFO and interrupt behavior interpretation
  • Alignment with evaluation hardware reference design

Getting Started

Requirements

Hardware

Info

This tutorial explicitly utilizes the DA14531 Pro Development Kit. However, you can also use the DA14531 USB Development Kit—just be sure to adjust your pin configurations and jumper settings accordingly.

  • DA14531 development board
  • MAX86141OSBEK
  • 0.3 mm pitch to 2.54 mm 25-pin FPC (flexible flat cable) adapter board
  • Jumper wires

Software

  • Keil uVision
  • DA14531 SDK6
  • J-Link or UART flashing tool

Hardware Preparation

The MAX86141 (Slave) is connected to the DA14531 Pro Development Kit (Master) using SPI mode.

Wiring Diagram

Note
  • J1 and J2 are general-purpose breakout headers from the DA14531 Pro Development Kit.
  • GPIO references in this guide correspond to pins exposed through these headers.
  • Wire colors are recommendations only and can be changed as needed.
  • SPI mode is used for this example.
  • INT is optional but recommended for interrupt/FIFO-based applications.
DA14531 + MAX86141 Wiring Diagram
Figure 1: DA14531 + MAX86141 Wiring Diagram

Pin Connections

MAX86141 Pin DA14531 Pin Function Wire Color
1.8V V3 Power (1.8v) Orange
VLED - Power (3.3v - 5v) Red
GND GND Ground Black
SPI0_SCK GPIO0_4 (SPI_CLK) SPI Clock Blue
SPI0_MOSI GPIO0_5 (SPI_DI) SPI MOSI Grey
SPI0_MISO GPIO0_1 (SPI_DO) SPI MISO Purple
SPI0_CSOPT_N GPIO0_3 (SPI_CS) Chip Select White
- GPIO0_6 UART TX Debug Brown

PPG Basic

Simple hardware validation and MAX86141 communication testing.

Features

  • SPI communication
  • Device ID verification
  • LED configuration
  • FIFO sample reading
  • Raw PPG data acquisition
  • UART debug logs

Intended Use

  • Sensor bring-up
  • Hardware debugging
  • Driver development
  • Optical signal validation

Get Started!

PPG Basic + BLE

This section is currently under development.

We’re actively working on it and will have updates available soon. Thank you for your patience!