Save the ADC data to SDRAM of Portenta H7 not works

[cornetlin]

Hi. we are trying to save the ADC data to SDRAM of Portenta H7, but not works. 
As you can see in the end of the code we use digitalWrite(LEDG, LOW); to see if the code go to there, but we never reach it. 
We don't know why.
Any suggestion?

Thanks

//#include "FATFileSystem.h"
//#include "SDMMCBlockDevice.h"
#include "SDRAM.h"

#define analogPin A5

//SDMMCBlockDevice block_device;
//mbed::FATFileSystem fs("fs");

// REDIRECT_STDOUT_TO(Serial);

void setup() {
  // put your setup code here, to run once:

  pinMode(A5, INPUT);
  pinMode(LEDB, OUTPUT);
  pinMode(LEDG, OUTPUT);

//    while(1){
//    int err =  fs.mount(&block_device);
//    if(err){
//     digitalWrite(LEDR, LOW); // Not detect the SD CARD
//     delay(50);
//    }else{
//     digitalWrite(LEDR, HIGH); //detect the SD CARD
//     break;
//    }
//     // int err = fs.reformat(&block_device);  // seriously don't want to format your good data
//  }

  SDRAM.begin();

  Serial.begin(115200);
  while (!Serial);
  analogReadResolution(16);
}

void loop() {
  // put your main code here, to run repeatedly:

  digitalWrite(LEDB, LOW);

  int arrSize = 1000, iter;
  analogReadResolution(16);
  unsigned int previousTime = 0;
  float ref_voltage = 5.0;

  uint16_t *analogVal =
      (uint16_t *)SDRAM.malloc(arrSize * sizeof(uint16_t)); // 2MB array;

  if (analogVal == NULL) {
    Serial.print("Oops, too big :)");
  }

  //int a = analogRead(analogPin);
  delay(1000);
  Serial.print("000");
  Serial.print("000");

  for (int iter = 0; iter < arrSize; iter++) {
    analogVal[iter] = analogRead(analogPin);
//    while (1) {
      // Pause 50 microseconds (the samping rate is 20000 sampling/s)
//      unsigned int currentTime = micros();
//      if (currentTime - previousTime >= 50) {
//        previousTime = currentTime;
//        break;
//      }
//    }
  }

//  char myFileName[] = "fs/01.txt";   // "fs/" needs to be there, think fileSystem
//  //
//  FILE *myFile = fopen(myFileName, "w");          // "a" for append (add to file), "w" write, "r" read ??
//  //
//  float adc_voltage = 0;
//  //int tem = 0;
//  for(iter = 0; iter < arrSize; iter++){
//  //adc_voltage  = (*(analogVal+iter) * ref_voltage) / 65536.0 * 1000.0;
//  fprintf(myFile,"%d\r\n",analogVal[iter]);
//  }
//  //
//  fclose(myFile);

  digitalWrite(LEDG, LOW);
  //Serial.print(analogVal[5326]);
  SDRAM.free(analogVal);
  //Serial.print("Finish");
  while (1)
    ;
}

[tjaekel]

I think the issue is: SDRAM is a class. You call .begin() directly on the class, NOT at an object.

I do this in my code:

#include <SDRAM.h>

[tjaekel]

Sorry, too early...

#include <SDRAM.h>

SDRAMClass sdram;

void setup() {
    //initialize SDRAM, even we do not use yet
    sdram.begin();
#if 0
    GsdramStart = (uint8_t*)sdram.malloc((8 * 1024 * 1024)/8 - 12);     //first 12 bytes are used for malloc?
#else
    GsdramStart = (uint8_t*)0x60000000;                                 //hard-coded start of SDRAM (bank 1, NOR/PSRAM)
#endif
    if (GsdramStart)
        strcpy((char*)GsdramStart, (const char *)"SDRAM");              //0x60000000, but string starts at 0x6000000C
    //before, on 0x60000008 seems to be the allocated length

I think, you need an instance of SDRAM, not SDRAM.begin() (on the class directly).

The fact, that you never reach this digitalWrite(LEDG, LOW) is:

• you crash when trying to write to SDRAM

• your code ends up in HardFaultHandler (do you see a red "morse-coding" LED?)

• your SDRAM was initialized (not enabled) via SDRAM.begin() (because you need instance of SDRAM and then sdram.begin())

This is the "trouble" with OOP, C++ on embedded system. You can have a CLASS.begin() method (a static function), but it is not the same as SDRAM sdram.begin() - now the constructor, the static function is not really a constructor).

You do not get a compile error when doing SDRAM.begin() ? Very strange, it should complain if static member function is not defined.

Try really:

SDRAM sdram;
sdram.begin();

instead of:

SDRAM.begin();

(and have an instance, object of SDRAM, not just the class definition only).