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ESP32 在Platform Arduino平台驱动外部PSAM，进行内存管理

ai 2025/5/7 12:30:11

一，基本介绍

本文中主要介绍ESP32、ESP32S3系列单片机，基于Vscode Platform Arduino和Arduino框架下如何使用外部PSAM，以及必要的API调用函数进行内存分配和管理。

使用前提是开发板有外部PSRAM。

二，平台配置

2.1 Arduino平台

2.2 Platform IO

; PlatformIO Project Configuration File
;
;   Build options: build flags, source filter
;   Upload options: custom upload port, speed and extra flags
;   Library options: dependencies, extra library storages
;   Advanced options: extra scripting
;
; Please visit documentation for the other options and examples
; https://docs.platformio.org/page/projectconf.html[env:esp32-s3-devkitc-1]
platform = espressif32
board = esp32-s3-devkitc-1
framework = arduino
;串口波特率
monitor_speed = 115200
;串口下载速度
upload_speed = 921600
;CPU的运行速度240Mhz
board_build.f_cpu = 240000000
;根据自己的开发板，选择分区表
board_build.partitions = default_16MB.csv
;外部PSRAM使用qio或者opi
board_build.arduino.memory_type = qio_opi
;通过该宏定义，启动外部的PSRAM
build_flags = -DBOARD_HAS_PSRAM
;外部Flash的大小
board_upload.flash_size = 16MB

三，内存测试代码

测试单片机为ESP32S3N16R8，具有16MB Flash 和8MB PSAM


#include <Arduino.h>
#include <esp_heap_caps.h>void setup() {Serial.begin(115200);//查看ESP32堆的总共大小Serial.printf("ESP32 total Heap size :%d bytes\n",ESP.getHeapSize());//查看ESP32堆的可用大小Serial.printf("ESP32 free  Heap size :%d bytes\n",ESP.getFreeHeap());//查看ESP32的Flash的大小Serial.printf("Flash size: %d bytes\n", ESP.getFlashChipSize());//查看ESP32的内部和外部RAM的总共大小Serial.printf("Deafult total size: %d bytes\n", heap_caps_get_total_size(MALLOC_CAP_DEFAULT));//查看ESP32的内部和外部RAM的可用大小Serial.printf("Deafult free size: %d bytes\n", heap_caps_get_free_size(MALLOC_CAP_DEFAULT));//查看ESP32的内部RAM总共大小Serial.printf("Internal total size: %d bytes\n", heap_caps_get_total_size(MALLOC_CAP_INTERNAL));//查看ESP32的内部RAM可用大小Serial.printf("Internal free size: %d bytes\n", heap_caps_get_free_size(MALLOC_CAP_INTERNAL));//查看ESP32的外部RAM的可用大小Serial.printf("PSRAM total size: %d bytes\n", heap_caps_get_total_size(MALLOC_CAP_SPIRAM));//查看ESP32的外部RAM的可用大小Serial.printf("PSRAM free size: %d bytes\n", heap_caps_get_free_size(MALLOC_CAP_SPIRAM));
}void loop() {delay(10); 
}

串口输出结果

四，内存申请与释放代码

测试单片机为ESP32S3N16R8

 //从芯片内部申请PSARAM，大小为1000字节，数据类型为char型char* str1=(char *)heap_caps_malloc(1000,MALLOC_CAP_INTERNAL);  //从芯片外部申请PSARAM，大小为1000字节，数据类型为char型char* str1=(char *)heap_caps_malloc(1000,MALLOC_CAP_SPIRAM);  //内存释放heap_caps_free(str);


#include <Arduino.h>
#include <esp_heap_caps.h>void setup() {Serial.begin(115200);Serial.printf("内部RAM可使用大小: %d bytes\n", heap_caps_get_free_size(MALLOC_CAP_INTERNAL));char* str=(char *)heap_caps_malloc(1000,MALLOC_CAP_INTERNAL);sprintf(str,"hello world! I am a handsome boy!");Serial.println(str);Serial.printf("内部RAM可使用大小: %d bytes\n", heap_caps_get_free_size(MALLOC_CAP_INTERNAL));Serial.printf("外部RAM可使用大小: %d bytes\n", heap_caps_get_free_size(MALLOC_CAP_SPIRAM));char* str1=(char *)heap_caps_malloc(1000,MALLOC_CAP_SPIRAM);sprintf(str1,"hello world! I am a pretty girl!");Serial.println(str1);Serial.printf("外部RAM可使用大小: %d bytes\n", heap_caps_get_free_size(MALLOC_CAP_SPIRAM));Serial.println("释放内存！");heap_caps_free(str); heap_caps_free(str1); Serial.printf("内部RAM可使用大小: %d bytes\n", heap_caps_get_free_size(MALLOC_CAP_INTERNAL));Serial.printf("外部RAM可使用大小: %d bytes\n", heap_caps_get_free_size(MALLOC_CAP_SPIRAM));}void loop() {delay(10); 
}

串口输出结果