Large array initialization in F28027 (Piccolo Controlstick)

Can somebody please reply to my question? 

If I can't define a big array in F28027, should I go for some other controlstick or controlcard..........

Please help......

Neha Aggarwal said:

Till now I can not declare an array of size greater than 1728 values

Why not?

What haveyou tried?

What was the result?

What have you done to resolve any issue(s) that you found?

Hello Andy,

First thing, I have defined a global array and if I declare arr[1400] it is fine but any number larger than that give an error  

"library "libc.a" run placement fails for object ".ebss", size 0x750 (page 1). Available ranges: DRAML0 size: 0x700 unused: 0x600 max hole: 0x600 .ebss : > DRAML0, PAGE = 1"

but then I went t RAM linker file and changed the length of DRAM in page 1. After that I could define larger array but when I compiled it and ran the code.

There were all zeros after 1728 value. (checked it through matlab)

I can attach my code if that can help.

Thank you so much.. 

Hello Brandon,

Thanks for your reply but I don't understand one thing. Why I need to have a 16-bit element? 12-bit ADC is enough for me. I want to take say 10000 samples from ADC in a single run so that I can process them later.

#include "DSP28x_Project.h"     // Device Headerfile and Examples Include File
#include <stdio.h>
// Prototype statements for functions found within this file.
interrupt void adc_isr(void);
void Adc_Config(void);


// Global variables used in this example:
Uint16 LoopCount;
Uint16 ConversionCount;
int Voltage2[1400];


main()
{
	   
    InitSysCtrl();
  	DINT;
	InitPieCtrl();

   IER = 0x0000;
   IFR = 0x0000;

   InitPieVectTable();


   EALLOW;  // This is needed to write to EALLOW protected register
   PieVectTable.ADCINT1 = &adc_isr;
   EDIS;    // This is needed to disable write to EALLOW protected registers


   InitAdc();  // For this example, init the ADC



// Enable ADCINT1 in PIE
   PieCtrlRegs.PIEIER1.bit.INTx1 = 1;	// Enable INT 1.1 in the PIE
   IER |= M_INT1; 						// Enable CPU Interrupt 1
   EINT;          						// Enable Global interrupt INTM
   ERTM;          						// Enable Global realtime interrupt DBGM

   LoopCount = 0;
   ConversionCount = 0;

// Configure ADC

	EALLOW;
	AdcRegs.ADCCTL1.bit.INTPULSEPOS	= 1;	//ADCINT1 trips after AdcResults latch
	AdcRegs.INTSEL1N2.bit.INT1E     = 1;	//Enabled ADCINT1
	AdcRegs.INTSEL1N2.bit.INT1CONT  = 1;	//Disable ADCINT1 Continuous mode
	AdcRegs.INTSEL1N2.bit.INT1SEL	= 2;	//setup EOC2 to trigger ADCINT1 to fire
	AdcRegs.ADCSOC2CTL.bit.CHSEL 	= 4;	//set SOC2 channel select to ADCINA2
	AdcRegs.ADCSOC2CTL.bit.TRIGSEL 	= 5;	//set SOC2 start trigger on EPWM1A, due to round-robin SOC0 converts first then SOC1, then SOC2
	AdcRegs.ADCSOC2CTL.bit.ACQPS 	= 6;	//set SOC2 S/H Window to 7 ADC Clock Cycles, (6 ACQPS plus 1)
	AdcRegs.ADCINTSOCSEL1.bit.SOC2 = 0;		// No ADCINT triggers SOC2.  TRIGSEL field determines trigger.
	AdcRegs.ADCCTL1.bit.ADCENABLE = 1;		// Enable the ADC
	EDIS;

// Assumes ePWM1 clock is already enabled in InitSysCtrl();
   
   EPwm2Regs.TBCTL.bit.CTRMODE = 0x3;		// Disable the timer

   EPwm2Regs.TBCTL.all = 0xC033;			// Configure timer control register
   EPwm2Regs.TBCTR = 0x0000;				// Clear timer counter
   EPwm1Regs.ETSEL.bit.SOCAEN	= 1;		// Enable SOC on A group
   EPwm1Regs.ETSEL.bit.SOCASEL	= 2;		// Select SOC from from CPMA on upcount
   EPwm1Regs.ETPS.bit.SOCAPRD 	= 1;		// Generate pulse on 1st event
   EPwm1Regs.TBPRD 				= 600;	// Set period for ePWM1
   EPwm1Regs.TBCTL.bit.CTRMODE 	= 0;		// count up and start

// Wait for ADC interrupt
   for(;;)
   {
      LoopCount++;
   }
}


interrupt void  adc_isr(void)
{
	  Voltage2[ConversionCount] = AdcResult.ADCRESULT2;

  if(ConversionCount == 1400)
	  {
	     ConversionCount = 0;
	  }
  else 
	 {
	  ConversionCount++;
	
	  AdcRegs.ADCINTFLGCLR.bit.ADCINT1 = 1;		//Clear ADCINT1 flag reinitialize for next SOC
	  PieCtrlRegs.PIEACK.all = PIEACK_GROUP1;   // Acknowledge interrupt to PIE
	 }


  return;
}

I have attached the file in case it can help. I want Voltage2[10000] which is right now Voltage2[1400].

Thanks

Neha Aggarwal said:

Thanks for your reply but I don't understand one thing. Why I need to have a 16-bit element? 12-bit ADC is enough for me. I want to take say 10000 samples from ADC in a single run so that I can process them later.

In order to hold all of the bits of the 12-bit ADC values, you need to have a storage element of that size or larger.  There is no 12-bit memory on the C2000 devices.  In reality, the fundamental element size of the C2000 family is 16-bit.  This is described in the TMS320C28x Optimizing C/C++ Compiler v6.0 User's Guide in Section 6.4 in the Data Types section.

BrandonAzbell said:

assuming you needed no RAM for your program variables, etc (which is not realistic), you could at most have a 6K (6 * 1024) buffer.

According to this, I should be able to define at least an arr[2000]. But I am getting all zeros after 1728 element in the buffer. Can you tell me why? 

Hello Brandon,

After what we have discussed here, it will be good for me to buy Piccolo F28069 having 100K (50K of 16-bit) RAM

Please correct me if I am wrong.

Thank you so much for the help.

Neha Aggarwal said:

I went t RAM linker file and changed the length of DRAM in page 1. After that I could define larger array but when I compiled it and ran the code.

There were all zeros after 1728 value. (checked it through matlab)

So you lied to the Linker about how much RAM your target has.

The Linker has no way to tell how much RAM your target has other than what you tell it in the Linker file - so, if you tell it that there's 0x750 when, in fact, there's only 0x700 that is obviously going to cause problems!

It's like telling a blind man to walk 300 metres along a 200-metre pier...!!

You are on the right path.