esp-idf/examples/system/ipc/ipc_isr

Supported Targets	ESP32	ESP32-S3

Hi-priority IPC example

This example demonstrates how to use Hi-priority IPC, it is based on Hi-priority interrupt (level 4). This feature can be useful in case when need quickly to get the state of the other CPU (consult the Hi-priority IPC). In the asm_funcs.S file are functions that will be run on the other core. The function should be fairly simple that can be written in assembler.

The first asm function get_ps_other_cpu() demonstrates a simple way of usage, it returns the PS register of other core.

The second asm function extended_ipc_isr_asm() demonstrates way when need to do some complex operations on other core, for this, save registers to the buffer (regs[]) making them available for use. Then using passed arguments (in[]) do some work and write the result to out[]. At the end recover saved registers.

How to use example

Hardware Required

Example should be able to run on any commonly available ESP32 development board. The chip should have two cores.

Configure the project

• CONFIG_FREERTOS_UNICORE - disabled,
• CONFIG_ESP_IPC_ISR_ENABLE - enabled.

idf.py menuconfig

Build and Flash

idf.py build flash monitor

(To exit the serial monitor, type Ctrl-].)

See the Getting Started Guide for full steps to configure and use ESP-IDF to build projects.

Example output

I (304) example: Start
I (304) example: call get_ps_other_cpu
I (314) example: PS_INTLEVEL = 0x5
I (314) example: PS_EXCM = 0x0
I (324) example: PS_UM = 0x1
I (324) example: call extended_ipc_isr_asm
I (324) example: in[0] = 0x1
I (334) example: in[1] = 0x2
I (334) example: in[2] = 0x3
I (334) example: out[0] = (in[0] | in[1] | in[2]) = 0x3
I (344) example: out[1] = (in[0] & in[1] & in[2]) = 0x6
I (354) example: out[2] = in[2] = 0x3
I (354) example: out[3] = PS of other cpu = 0x25
I (364) example: End