how to recieve input from PC keyboard on target in a debug session

[ferro]

Hi,

With Keil uVision I could type to a console and reicieve that on target with SER_GetChar ().
I implemented SER_GetChar () but the code below does not go to case 'a'.

switch ( SER_GetChar() )
{
	case 'a' :
		dbg_print ( "Pressed 'a'\n" );
		break;
	default :
		break;
}

What am I doing wrong ?

Any idea how to recieve input from PC keyboard on target in a debug session, to replicate uVision's functionality ?

Thank you

[Andrew Neil]

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@ferro wrote:

With Keil uVision I could type to a console and receive that on target with SER_GetChar ().

---

You've posted this in the STM32CubeIDE section - does this mean that you're now trying to get the same thing working in CubeIDE?

You'll need to show your implementation of SER_GetChar() - see the Posting Tips for how to post source code:

 https://community.st.com/t5/community-guidelines/how-to-write-your-question-to-maximize-your-chances-to-find-a/ta-p/575228

Is it receiving anything at all ?

What board are you using, and how is it connected to the PC?

[Andrew Neil]

https://community.st.com/t5/stm32-mcus/how-to-use-the-stm32cubeide-terminal-to-send-and-receive-data/ta-p/49434

https://www.youtube.com/watch?v=JWOV4j5fCS4

https://www.youtube.com/playlist?list=PLnMKNibPkDnFCosVVv98U5dCulE6T3Iy8

[ferro]

@Andrew Neil, thanks for prompt reply. I use CubeIDE 1.16.1, custom board and STLink v3.

extern volatile int32_t ITM_RxBuffer;
volatile int32_t        ITM_RxBuffer = ITM_RXBUFFER_EMPTY;


int SER_GetChar (void)
{
    return ITM_ReceiveChar();
}

Breakpoint at Line 2687 is never reached.

[mƎALLEm]

Hello @ferro ,

AFAIK, you need to retarget the "get char" to the ITM:

volatile int32_t ITM_RxBuffer=ITM_RXBUFFER_EMPTY; 

int __io_getchar(void)
{
   return ITM_ReceiveChar();
}

Inspired from this thread: 

https://community.st.com/t5/stm32-mcus-products/itm-receivechar-void-gives-undefined/td-p/538168

[Andrew Neil]

Right, so you're using the Instrumentation Trace Macrocell (ITM):

https://www.youtube.com/watch?v=-X8tndfqTu8

https://www.st.com/resource/en/user_manual/um2609-stm32cubeide-user-guide-stmicroelectronics.pdf#page=182

https://wiki.st.com/stm32mcu/wiki/Category:STM32CubeIDE

[mƎALLEm]

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@ferro wrote:

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This means that you didn't receive any character as the buffer is empty according to the if condition.

Also, look at this article. It may help.

[ferro]

Thanks @mƎALLEm , so far no success with your __io_getchar().

https://community.st.com/t5/stm32-mcus/how-to-use-semihosting-with-stm32cubeide-and-stm32/ta-p/49742

Thanks, might try that next.

I remembered ITM settings in uVision - is something similar in Cube ? Is ITM in Cube set for semihosting internally ?

Clearly it is a black magic to me. I checked what ITM is - part of Cortex M debuging suite. So, is not this supported by STLink ? There is GBD, STLink, some code on target, Cube. Anything else in the chain ? Cannot be Cube in control of this chain so that console printf/read is woking smoothly ? Very confusing.

@Andrew Neilthanks for the links, will take some time to get through them.

"Right, so you're using the Instrumentation Trace Macrocell (ITM):"

As I said, I have no clue what I am doing. Just trying to copy what is working (ITM) on my other project (Cortex M3, Ulink, uVision, clang) where someone else got it working. It does not need to be ITM.

[mƎALLEm]

See this video, especially at @1:12 for ITM configuration.

[Andrew Neil]

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@ferro wrote:

It does not need to be ITM

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A common(er?) alternative would be to use a UART instead - that was the focus of my 2nd reply.