give me a sample code to use psram

As an AI language model, I don't have access to physical devices or hardware. However, here's an example code to use PSRAM in an ESP32 board:

#include <Arduino.h>
#include <esp_heap_caps.h>

// Define the size of the PSRAM to be used
#define PSRAM_SIZE 32768

void setup() {
  // Initialize the PSRAM
  if (heap_caps_malloc(PSRAM_SIZE, MALLOC_CAP_SPIRAM)) {
    Serial.println("PSRAM initialized successfully!");
  } else {
    Serial.println("PSRAM initialization failed!");
  }
}

void loop() {
  // Access the PSRAM as needed
}

This code initializes the PSRAM in an ESP32 board by allocating a specified amount of memory using the `heap_caps_malloc()` function. The `MALLOC_CAP_SPIRAM` flag is used to indicate that the memory should be allocated in the PSRAM instead of the internal RAM.

Once the PSRAM is initialized, it can be accessed as needed in the `loop()` function. Note that the PSRAM can be accessed using standard memory access functions such as `malloc()` and `free()`.