WFI - Standby mode demo

Table of Contents

• Introduction
• Supported Combinations
• Steps to Run the Example
• See Also
• Sample Output

Introduction

This example showcases the use of WFI instruction to put one core in standby mode while the main core measures the current value before and after the standby period with the help of on-board I2c based INA current monitors. The example specifically focuses on a dual-core setup with cores R5 Cluster 0 and R5 Cluster 1 running in lockstep mode underlying no-RTOS environment on the supported SOC.

The example does the below

• Initialize the system and configure the necessary interrupts and IPC mechanisms
• Configure both cores to operate in lockstep mode, ensuring synchronized execution.
• Initialize and set-up the current monitors
• Main core measures the current value and send an IPC notify message to the secondary core to enter into wfi mode.
• Main core measures the current value again after the standby period and compare the difference with the expected value.

Supported Combinations

Parameter	Value
CPU + OS	r5fss0-0 nortos
Toolchain	ti-arm-clang
Boards	am243x-evm
Example folder	examples/kernel/nortos/wfi_standby_demo/

Steps to Run the Example

• When using CCS projects to build, import the CCS project for the required combination and build it using the CCS project menu (see Using SDK with CCS Projects).
• When using makefiles to build, note the required combination and build using make command (see Using SDK with Makefiles)
• Launch a CCS debug session and run the executable, see CCS Launch, Load and Run

See Also

Driver Porting Layer (DPL)

Sample Output

Shown below is a sample output when the application is run,

[MAIN_Cortex_R5_0_0] [I2C] INA found at device address 0x40
[WFI] Values before wfi !!!
[WFI] power= 1435 mW , current=841300 uA
[WFI] Values after wfi !!!
[WFI] power= 1320 mW , current=773800 uA
[WFI] Actual Power Drop = 115 mW
All tests have passed!!