PicoPlusPsram

Classes for accessing PSRAM on a Pimoroni Pico Plus 2.

This is basically a wrapper around lwmem with a C++ BaseClass to inherit from for any classes you want to dynamically store in PSRAM, and a C++ Allocator.

Basics

PicoPlusPsram is a singleton and can be accessed using PicoPlusPsram::instance()

To check for available memory:

PicoPlusPsram &ps = PicoPlusPsram::getInstance();

size_t uMemorySize = ps.GetMemorySize();

if uMemorySize is 0, you have no PSRAM or something terrible has gone wrong.

if you need to know how much PSRAM you still have available:

PicoPlusPsram &ps = PicoPlusPsram::getInstance();

size_t uStartFreeMem = ps.GetAvailableBytes();

C Style Allocations

Malloc, Calloc, Realloc and Free are implemented.

eg:

PicoPlusPsram &ps = PicoPlusPsram::getInstance();

void *pMem = ps.Malloc(1024);

C++ goodies

If you want your objects to be dynamically stored in PSRAM then inherit from PicoPlusPsram::BaseClass

eg:

#include "PicoPlusPsram.h"

class TestClass : public PicoPlusPsram::BaseClass
{
public:
  TestClass(uint32_t uVal) : m_uVal(uVal) {};
  ~TestClass(void) {}

  uint32_t Get(void)
  {
    return m_uVal;
  }
private:
  uint32_t  m_uVal;
};

Now if you new this class it will be stored in psram.

TestClass *pImInPsram = new TestClass(1);

There is also a C++ allocator PicoPlusPsram::Allocator

This can be used anywhere an allocator is needed, eg:

std::vector<int, PicoPlusPsram::Allocator<int>> vInPsram;
vInPsram.push_back(1);
vInPsram.push_back(2);

adding to your own projects

`PicoPlusPsram.h" and 'PicoPlusPsram.cpp' need to be added to your project.

lwmem also needs adding to your project from https://github.com/MaJerle/lwmem

If you want the available memory functionality then LWMEM_CFG_ENABLE_STATS has to be set to 1

In this test project this is done with the file lwmem_opts_ppp.h", and set(LWMEM_OPTS_FILE ${CMAKE_CURRENT_LIST_DIR}/lwmem_opts_ppp.h)` in the CMakeLists.txt

Notes:

The c++ allocation and new stuff should really be thowing exceptions, but this seems to be disabled by default for the pico builds.

PicoPlusPsram::Detect and PicoPlusPsram::Init are from: https://github.com/pimoroni/micropython

lwmem from: https://github.com/MaJerle/lwmem and is a submodule so make sure you fetch that.

Test.cpp and TestClass.h test out the functionality, best to start there.

This is not thread safe at the moment, only use it from one core!

I will update it to be thread safe...