add platformio pimoroni rp2350 PSRAM demo

Author: webzep

libraries/rp2350/examples/PlatformioPSRAMDemo/PsramAllocator.h

@@ -0,0 +1,38 @@
+#ifndef PSRAM_ALLOCATOR_H
+#define PSRAM_ALLOCATOR_H
+
+#include <Arduino.h>
+
+extern "C"
+{
+	void *pmalloc(size_t size);
+}
+
+template <class T>
+struct PsramAllocator
+{
+	using value_type = T;
+
+	PsramAllocator() noexcept {}
+	template <class U>
+	PsramAllocator(const PsramAllocator<U> &) noexcept {}
+
+	T *allocate(std::size_t n)
+	{
+		if (auto p = static_cast<T *>(pmalloc(n * sizeof(T))))
+		{
+			return p;
+		}
+		throw std::bad_alloc();
+	}
+
+	void deallocate(T *p, std::size_t /*n*/) noexcept
+	{
+		if (p)
+		{
+			free(p);
+		}
+	}
+};
+
+#endif // PSRAM_ALLOCATOR_H

libraries/rp2350/examples/PlatformioPSRAMDemo/README.md

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+# PlatformIO PSRam Pimoroni Pico 2 (2350) Demo
+
+This shows the PlatformIO config and a simple helper struct to use the PSRAM instead of the SRAM.
+
+Include the relevant entries from the platformio.ini file. Then import the PsramAllocator file and use it like so:
+
+```cpp
+
+// Before
+// std::vector<uint16_t> pageBuffer;
+
+// After
+static std::vector<uint16_t, PsramAllocator<uint16_t>> pageBuffer;
+
+pageBuffer.size(SCREEN_WIDTH * SCREEN_HEIGHT);
+```

libraries/rp2350/examples/PlatformioPSRAMDemo/main.cpp

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+#include <Arduino.h>
+#include <vector>
+#include "PsramAllocator.h"
+
+// A vector that uses your PsramAllocator, so its buffer is in PSRAM.
+static std::vector<int, PsramAllocator<int>> psramVector;
+
+void setup()
+{
+	Serial.begin(115200);
+	delay(5000);
+
+	Serial.println("PSRAM Allocator Demo Start");
+
+	// Show how much PSRAM was detected
+	Serial.print("Detected PSRAM size: ");
+	Serial.println(rp2040.getPSRAMSize());
+
+	// Reserve space in the PSRAM vector
+	psramVector.resize(100);
+	
+    // Write some values
+	for (size_t i = 0; i < psramVector.size(); i++)
+	{
+		psramVector[i] = i * 2; // e.g. fill with even numbers
+	}
+
+	Serial.println("Data written to psramVector in external PSRAM.");
+
+	delay(1000);
+
+    // Read them back
+	Serial.println("Reading back the first 10 elements:");
+	for (size_t i = 0; i < 10 && i < psramVector.size(); i++)
+	{
+		Serial.print("psramVector[");
+		Serial.print(i);
+		Serial.print("] = ");
+		Serial.println(psramVector[i]);
+	}
+}
+
+void loop()
+{
+}

libraries/rp2350/examples/PlatformioPSRAMDemo/platformio.ini

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+[env:rpipico2]
+platform = https://github.com/maxgerhardt/platform-raspberrypi.git
+build_flags = -fexceptions
+			 -DRP2350_PSRAM_CS=47
+board = rpipico2
+board_build.core = earlephilhower
+board_build.pico_boot2_name = boot2_psram8.S
+board_build.pico_psram_size = 8
+board_upload.psram_length = 8388608
+framework = arduino
+lib_deps = 
+	SPI