External register for flash memory files, on T4.1

[Sandro]

Hi all! In my audio application, I need to open many audio files (stored in the external flash chip on the Audio Adaptor) in the "same time".
Each activity with an audio file starts with:

SerialFlashFile rawfile;
rawfile = SerialFlash.open(file_name);

SerialFlash.open looks for file attributes (address, length, offset, dirindex), if file_name exist, on flash chip, reading on its "file-index" than copies these values into rawfile:

rawfile.address = buf[0];
rawfile.length = buf[1];
rawfile.offset = 0;
rawfile.dirindex = index + i;

This process takes on average about 50us, due to the read time of the flash: a relatively long time, considering the available time (about 2900us) that I reserve for completing the update() process.

So, instead of using SerialFlash.open, my idea is:
1) read all files attributes on flash chip (address, length, offset, dirindex) at setup() time and save these data in a RAM repository:

#define n_files 500
struct flashfile_data
{
  uint32_t address;
  uint32_t length;
  uint16_t dirindex;
} rawfiledata[n_files];

2) compile rawfile data.

The first part is very easy to do, since there are existing methods in SerialFlashFile class; the second is less trivial because rawfile is (rightly) protected; these assignments are not immediately possible :

rawfile.address = rawfiledata[i].address;
rawfile.length = rawfiledata[i].length;
rawfile.offset = 0;
rawfile.dirindex = rawfiledata[i].dirindex;

I've tried in to write a class that inherits from SerialFlashFile, but I cannot find a way to open the lock. Of course, I don't want to modify anything SerialFlash library; I would only create a minimum overlay for my purpose.
Thanks in advance for any idea!

 

[Sandro]

Solved! I had neglected to code the new derived class constructor!:

class HSerialFlashFile : public SerialFlashFile
{
public:
    HSerialFlashFile() : SerialFlashFile() {}
    void setAddress(uint32_t newAddress, ....)
    {
       this->address = newAddress;
       ....
    }
};