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how to transmit data via SWO STM32H743

LJack.3
Associate

I can not start transfer via SWO to STM32H743.

Port PB3 initialized clock feed.

Initialized SWO:

*(__IO uint32_t*)(0x5C001004) |= 0x00700000; // DBGMCU_CR D3DBGCKEN D1DBGCKEN TRACECLKEN
 
     //UNLOCK FUNNEL
     *(__IO uint32_t*)(0x5C004FB0) = 0xC5ACCE55; // SWTF_LAR
     *(__IO uint32_t*)(0x5C003FB0) = 0xC5ACCE55; // SWO_LAR
 
     //SWO current output divisor register
     //This divisor value (0x000000C7) corresponds to 400Mhz
     //To change it, you can use the following rule
     // value = (CPU Freq/sw speed )-1
      *(__IO uint32_t*)(0x5C003010) = ((SystemCoreClock / 2000000) - 1); // SWO_CODR
 
     //SWO selected pin protocol register
      *(__IO uint32_t*)(0x5C0030F0) = 0x00000002; // SWO_SPPR
 
     //Enable ITM input of SWO trace funnel
      *(__IO uint32_t*)(0x5C004000) |= 0x00000001; // SWFT_CTRL
 
     // Configure GPIOB pin 3 as AF
      *(__IO uint32_t*)(0x58020400) = (*(__IO uint32_t*)(0x58020400) & 0xffffff3f) | 0x00000080;
 
     // Configure GPIOB pin 3 Speed
      *(__IO uint32_t*)(0x58020408) |= 0x00000080;
 
     // Force AF0 for GPIOB pin 3
      *(__IO uint32_t*)(0x58020420) &= 0xFFFF0FFF;
 
 uint32_t SystemCoreClock = 480000000;

include printf:

int _write ( int file, char *ptr, int len )
{
  int i = 0;
  for ( i = 0; i < len; i++ )
    ITM_SendChar ( *ptr++ );
  return len;
}

Calls when passing a message through printf (); Checked set the brepoint in _write the moment the transfer is called

I checked the PB3 leg with an oscilloscope there is no signal.

The call to _write is passed to ITM_SendChar (* ptr ++); there is.

What is the matter, I ask for help.

_________________________

Gordon Bullard & Company

2 REPLIES 2

The ST-LINK/V2 on the original NUCLEO-H743ZI ran at 2 MHz

The frequency on the ZI2 version with the ST-LINK/V3 ran a lot faster.

I'd probably bring up the STM32 Cube Programmer SWV Window, and change the 2000000 to 24000000 or whatever you've selected as the connection speed. It's a ratio between the MCU clock, and the SWD clock..

The familiar looking code also assumes GPIOB clock has been enabled.

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Up vote any posts that you find helpful, it shows what's working..
Nikita91
Lead II

In my code I have an ITM initialization:

// Configure ITM
	ITM->LAR	= 0xC5ACCE55 ;		// ITM Lock Access Register, C5ACCE55 enables more write access to Control Register 0xE00 :: 0xFFC
	ITM->TCR	= 0x00010001 ;		// ITM Trace Control Register
	ITM->TPR	= ITM_TPR_PRIVMASK_Msk ;	// ITM Trace Privilege Register. All stimulus ports
	ITM->TER	= portMask ;			// ITM Trace Enable Register. Enabled tracing on stimulus ports. One bit per stimulus port.

 ITM/SWO works only in debug mode