MAXREFDES9002: C-source Reference for Operating the DS28E18 from Cortex-M4 GPIO Pins


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The DS28E18 is an easy-to-use bridge integrated circuit (IC) that operates as a 1-Wire® slave device to a host controller. The IC provides a 512-byte command sequencer loaded with commands and control data to operate an I2C or SPI device interfaced to the DS28E18. Once loaded, the host controller sends a 1-Wire command to autonomously execute the sequence, power, and collect data from the attached peripherals. A subsequent 1-Wire command reads the collected data. The power for the attached sensors or peripherals is sourced from the 1-Wire line, enabling a very efficient solution to remotely power and control complex devices such as environmental sensors, analog-to-digital converters (ADCs), digital-to-analog converters (DACs), and display controllers. The MAXREFDES9002 is a reference design showcasing the DS28E18 that demonstrates how to implement a simple 1-Wire master using only a microcontroller’s GPIO pins. To demonstrate this, this reference design provides a GPIO-based 1-Wire library designed for an ARM® Cortex® M4 microcontroller, such as the MAX32660, with example programs for interfacing an I2C or SPI device connected to a DS28E18.


  • Power and communication to I2C and SPI sensors through two wires
  • 512-byte command sequencer for autonomous operation
  • Up to 10mA at 3.3V sensor power derived from 1-Wire
  • Up to 100m distance with the 1-Wire interface
  • Example C-code demonstrates how to interface to I2C and SPI sensors


Designed, Built, Tested

Board pictured here has been fully assembled and tested. Not available for sale.



PCB Layout

Maxim Devices (2)

Part Number Name Product Family Order Design kits and evaluation modules
DS28E18 1-Wire® to I2C/SPI Bridge with Command Sequencer Secure Authentication Buy Now
MAX32660 Tiny, Ultra-Low-Power Arm Cortex-M4 Processor with FPU-Based Microcontroller (MCU) with 256KB Flash and 96KB SRAM MCU - Microcontroller Buy Now

Maxim Devices (2)

Part Number Product Family
Secure Authentication
1-Wire® to I2C/SPI Bridge with Command Sequencer
MCU - Microcontroller
Tiny, Ultra-Low-Power Arm Cortex-M4 Processor with FPU-Based Microcontroller (MCU) with 256KB Flash and 96KB SRAM

Design Files (3)

Title Type Size Date
MAXREFDES9002 BOM XLSX 13KB 2021-04-28
MAXREFDES9002 PCB PDF 578KB 2021-04-28
MAXREFDES9002 Schematic PDF 353KB 2021-04-28
Date Type


(XLSX, 13KB)



(PDF, 578KB)


MAXREFDES9002 Schematic

(PDF, 353KB)

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