Power Monitoring (PAC1934) on SAM9X75 Curiosity Development Board Using MPLAB® Harmony Application

Last modified by Microchip on 2025/05/19 12:28

Introduction

In this training topic, you will learn how to measure power consumption on the SAM9X75 Curiosity Development Board using the PAC1934 power monitoring Integrated Circuit (IC). This guide provides comprehensive instructions on utilizing the PAC1934 IC via Inter-Integrated Circuit (I²C) or USB interfaces to monitor power usage effectively.

SAM9X75-Curiosity

The PAC1934 is a versatile power monitoring IC that can measure voltage, current, power, and energy across four channels. This allows you to monitor the power consumption of various components on the SAM9X75 curiosity development, including the CORE, CPU, DDR and 3.3V power supply. This capability is particularly useful for analyzing power consumption in different applications without the need for additional hardware.

PAC Channels	Description
PAC1934 Channel 1	Core
PAC1934 Channel 2	DDR & IO
PAC1934 Channel 3	VDD 3V3
PAC1934 Channel 4	DC-DC

Note: For more details, refer to the "SAM9X75-Curiosity User Guide" document section, “DC Power Monitoring”.

There are two primary methods for measuring and monitoring power using the PAC1934 power monitoring IC:

Method 1: To measure the power via PAC193X Windows^® GUI
Method 2: To measure the power via I²C interface

Both methods are comprehensively detailed in the sections below, providing step-by-step instructions to ensure accurate power monitoring and measurement.

Hardware Used

SAM9X75 Curiosity Development Board
MPLAB^® PICkit™ 5
Two USB 2.0 Micro-B cables
MPLAB ICD 4 and MPLAB PICkit 4 Target Adapter Board
UART-TTL cable
microSD card

Software Used

Hardware Setup

Connect the USB 2.0 Micro-B cable to connector J2 (USB_A) to power up the board.

Connect the USB 2.0 Micro-B cable to connector J37 (PAC) to monitor the power.

Connect the UART-TTL cable to connector J35 (UART DEBUG).

Remove/open the jumper from connector J10 to disable QSPI boot & connector J9 to disable NAND boot.

Close pin 1 and 2 of Jumper J38.

Close pin 1 and 2 of Jumper J39.

J38 and J39 jumper settings are required to measure power via USB. For more details, refer to the power measurement I²C connection PAC1934 table in the SAM9X75 Curiosity Development Board.

Hardware setup

Measuring/Monitoring the Power Using PAC1934

Method 1: To Measure the Power via PAC193X Windows GUI

Download and Install the PAC193X Windows GUI Application.

Close pin 2 and 3 of Jumper J38.

J38 and J39 jumper settings are required to measure power via SAM9X75. For more details, refer to the power measurement I²C connection PAC1934 table in the SAM9X75 Curiosity Development Board.

Power Measurement I2C Connection PAC1934 Table

Open the PAC193X Windows GUI application. Select the device, go to Setting > Set constants > Sense Resistor Value, and set the sensing resistor value to 0.01 Ohm for four channels.

PAC1934 Demo Application settings

Note: For more details about Sense Resistor Values, refer to the "SAM9X75-Curiosity User Guide" document section, “DC Power Monitoring”.

Ensure the device is connected to the PAC193X Windows GUI application. In the PAC settings, select BiDirectional I measurement. In the Plot window, choose the measurement type, such as Power or Current, based on your monitoring needs.

Pac Settings and Status

Measurement Types

Note: Refer to the table in the introduction to identify which PAC channel measures the power for CORE, CPU, DDR, and 3.3V.

Click the Start Acquisition button in the PAC193X Windows GUI application.

PAC1934 Demo Application Start acquisition

Run any application in the SAM9X75 Curiosity Development Board and monitor the power or current on the PAC193X Windows GUI application.

PAC193X Windows GUI Application

Method 1 Summary

In Method 1, we learned how to configure the SAM9X75 Curiosity Development Board and the PAC193 demo application on Windows to monitor the power consumption of various components, including the SAM9X75 Core, DDR_IO, DC-DC, and 3V3_VDD. This approach provides asynchronous monitoring as it does not rely on the SAM9X75 for power measurement.

Method 2: To Measure the Power via I2C

Download the PAC1934 generic library v1.2.

Open MPLAB X IDE from the main menu.

Create a new project by clicking the New Project icon or by selecting File > New Project.

In the New Project window, under Projects, choose Application Project(s) and click Next.

Create Project

In the Select Device pane, fill in or select the information for below:

Family: 32-bit MCUs and MPUs(PIC32C/SAM)
Device: SAM9X75D2G

Select Device

In the Select Compiler pane, for Compiler Toolchains select XC32 Compiler, and click Next.

Select compiler

Enterthe Project Location, Project Folder and Project Name. Click Finish.

Project Name

After the project is created, MPLAB Code Configurator (MCC) will be automatically launched. (To launch MCC manually from the main menu, click on Tools > Embedded > MPLAB Code Configurator or click the MCC button in the MPLAB X IDE toolbar.) It will launch MCC Content Manger Wizard. Then select MPLAB Harmony.

MCC wizard

Check the required packages (csp, bsp, core, dev_packs) and click Finish. Content download will take some time. Wait till all the content is downloaded.

MCC wizard

In the project graph, add the Board Support Package (BSP) for SAM9X75 Curiosity from Device Resource. Then, from Device Resource > Peripheral, add DBGU, FLEXCOM7 and TC0. These modules and configurations are required to run the demo application.

Project graph

Pinout

Note: To know more details about how to add modules in the project graph, refer to the "Developing a USB Host Demo Application" section in the "USB Host Getting Started Application on SAM9X75 Early Access Evaluation Board" page.

Save all and then click the Generate button. This will generate code for all the device resources that have been added in the project graph.

MCC project generate

There is a library folder inside the PAC1934 generic library v1.2. In that folder, PAC193x.h and PAC193x.c files are available.

Add the PAC193x.h in header files and PAC193x.c in Source Files of the project.

Add PAC header Add Project source

Functions to be called from application to monitor power/current via I2C are as follows:

PAC193x_Device_Initialize(): Initializes the PAC1934 device
PAC193x_RefreshV(): This commands is used before reading the register of PAC1934
PAC193x_GetVBUSn_mV(): To get the V_Bus voltage in millivolts
PAC193x_GetVPOWERn_mW(): To get the V_Power voltage in milliwatts
PAC193x_GetEnergy_mWh(): To get the Energy in milliwatt-hours
PAC193x_GetISENSEn_AVG_mA(): To get the average current in milliamps

Refer to main.c for demo code.

Run the Harmony Application

Connect the J38 and J39 jumpers to SAM9X75, which will connect PAC1934 to SAM9X75. Refer to the Power measurement I²C connection PAC1934.

Jumper settings

Connect the USB 2.0 Micro-B cable in J2 (USB_A) to power up the board.

Take a microSD card formatted with FAT32 file system.

Download the pre-built binaries and copy the boot.bin and harmony.bin files to the microSD card.

Insert the microSD card to J14 on the SAM9X75 Curiosity Development Board.

Perform a reset by pressing RESET button on the SAM9X75 Curiosity Development Board.

PAC1934 power monitoring can be done through SAM9X75 Curiosity Development Board using pre-built application.

Open the terminal to see the output.

Serial Outputs

Method 2 Summary

In Method 2, we learned how to create, configure, build, and run a project using the MPLAB Harmony v3 software framework within MPLAB X IDE. This method enables power consumption monitoring directly using the SAM9X75, eliminating the need for external software. Additionally, this approach allows for real-time integrated monitoring of power usage across various components, providing a streamlined and efficient solution for power analysis on the target hardware.

Results

The following results are recorded while running ROM BOOT without loading AT91 and MPLAB Harmony application.

ROM BOOT
VDDCORE (1.15V)		VDDIODDR (1.35V)		VDD_3V3 (3.3V)
45 mA	14.9 mW	8 mA	0.01W	87 mA	10.4 mW

The following results are recorded while running AT91Bootstrap without the MPLAB Harmony application. AT91Bootstrap loaded from an SD card.

AT91Bootstrap (SD Card)
VDDCORE (1.15V)		VDDIODDR (1.35V)		VDD_3V3 (3.3V)
40 mA	13 mW	8 mA	0.0097W	118 mA	13.5 mW

The following results are recorded while running MPLAB Harmony application with endless loop from JTAG.

Clock Speed			Endless application with JTAG
CPU CLK (MHz)	MAIN SYSTEM BUS CLK (MHz)	DDRAM CLK (MHz)	VDDCORE (1.15V)		VDDIODDR (1.35V)		VDD_3V3 (3.3V)
800	266	266	40 mA	13 mW	8 mA	1.0 mW	129 mA	14.8 mW


600	200	200	37 mA	12.2 mW	9 mA	1.1 mW	101.5 mA	11.6 mW


400	133	133	40 mA	13 mW	10 mA	1.2 mW	102 mA	11.6 mW

The following results are recorded while running the MPLAB Harmony application from JTAG.

Clock Speed			Application (I2C + UART + JTAG)
CPU CLK (MHz)	MAIN SYSTEM BUS CLK (MHz)	DDRAM CLK (MHz)	VDDCORE (1.15V)		VDDIODDR (1.35V)		VDD_3V3 (3.3V)
800	266	266	49.744 mA	163.414 mW	7.019 mA	8.032 mW	129.089 mA	148.251 mW


600	200	200	46.997 mA	154.393 mW	7.935 mA	9.081 mW	104.065 mA	119.512 mW


400	133	133	43.945 mA	144.696 mW	7.935 mA	9.143 mW	78.735 mA	90.289 mW

Clock Speed			MIPI@60MHz
CPU CLK (MHz)	MAIN SYSTEM BUS CLK (MHz)	DDRAM CLK (MHz)	VDDCORE (1.15V)		VDDIODDR (1.35V)		VDD_3V3 (3.3V)
800	266	266	59 mA	19.5 mW	9 mA	10 mW	185 mA	21 mW


600	200	200	45 mA	14.5 mW	8 mA	8 mW	112 mA	12.5 mW


400	133	133	40 mA	13 mW	8 mA	8 mW	110 mA	12.5 mW