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Problem setup in Logic Analyzer in keil

Associate II
Posted on February 11, 2016 at 17:04

I use STM32f103RCT6 to blinking led in pin A8 with 1 second delay, and i try to use logic analyzer to see whether it's right. However, when i setup in ''Current Logic Analyzer Signal'', i write PA.8 in it and it say ''Unknown Signal''. I was trying write everything ''PORTA.8'',''PortA.8'',''PA8'' but it always say ''Unknown Signal''. What signal' name i should write in it???


Rashad Shubita
Associate III
Posted on January 18, 2018 at 13:46

Please anyone can help us! I read various documentation such as :

Using ST-Link/V2 and MDK 5 with Discovery/Nucleo Boards



but the same problem appears!

Thanks in advance.
Posted on January 18, 2018 at 16:49

Contact Keil support?

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Posted on January 18, 2018 at 16:54

Hi Clive,

No, becuse I think i am doing something wrong, but I don't what is it!

Alex R
Posted on January 18, 2018 at 22:46


Keil's Logic Analyzer is not a 'hardware' logic analyzer, and do not monitor I/O pins. It is also limited by the debugger and the MCU core you are using.

See below.




From Keil uVision User's Guide: Logic Analyzer

µVision User's Guide: Restrictions


When debugging on hardware, the number of items that can be defined in the

is restricted by the microcontroller core (refer to Access Breakpoints in

). Many more different items can be defined in simulation mode.

The Logic Analyzer can record changes of:

  • Global program variables, including


  • that represent I/O pins of the microcontroller.
  • Peripheral registers that are triggered by external or internal events, but with the restrictions outlined below.

The Logic Analyzer


record changes of:
  • Automatic variables defined inside a function

    Automatic variables are located on the stack or in overlayable memory regions. It is not possible to record changes of dynamic memory locations.
  • CPU registers

    CPU registers cannot be triggered with read or write breakpoints. Therefore, such changes cannot be recorded.
  • Peripheral registers that represent timer registers

    Increments of timers (or similar peripherals) are not simulated. Instead, the timing of events that are triggered by a timer, is calculated. Therefore, it is not possible to view timer increments.
  • I/O pins of communication peripherals

    I/O pin toggling of UART, CAN, SPI, or I²C communication peripherals is not simulated. It is assumed that the timing of communication streams behaves according to the specifications. Instead, the I/O stream is represented by VTREGs.
  • Memory BUS signals

    µVision simulates a CPU including memory areas, but it does not simulate the Memory BUS signals (data BUS, address BUS, and control lines like RD, WR, ALE). Therefore, it is not possible to view memory BUS signals with the Logic Analyzer
Associate II

I have the same problem and I cannot find any solution for it. If you've found a solution, please let me know.

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