{"id":2128,"date":"2016-02-06T10:33:30","date_gmt":"2016-02-06T09:33:30","guid":{"rendered":"https:\/\/playembedded.org\/?p=2128"},"modified":"2020-04-17T21:09:31","modified_gmt":"2020-04-17T19:09:31","slug":"mikroe-clicker-2-for-stm32-and-stlink-v2","status":"publish","type":"post","link":"https:\/\/playembedded.org\/blog\/mikroe-clicker-2-for-stm32-and-stlink-v2\/","title":{"rendered":"Mikroe Clicker 2 for STM32 and STLink v2"},"content":{"rendered":"

Introduction<\/h3>\n

In this tutorial we are going to see how to connect a STLink v2 debugger to a Clicker 2 for STM32 enabling users to do debugging which could be very useful in development phases. A debugger is a computer program which is used to test and debug another program usually named Target.<\/p>\n

In embedded things are slightly different since the code is executed on an external MCU and it is required an interface Computer-MCU. In this case the Target<\/i> is the MCU and a debugger is composed by the ensemble of a hardware and a software tool. Nonetheless, when the majority of people is talking about debugger,they are referring only to the hardware part.<\/p>\n

A debugger allows the connection to a Target enabling the Host<\/b> to load a firmware on it managing its code execution, allowing the inspection of its registers and much more. To do this, it uses some specific commands that usually depend on the MCU architecture: this means that there are specific debuggers for specific MCUs. The STLink v2 is a low cost debugger supporting both STM32<\/b> and STM8<\/b>. In what follows we are going to use OpenOCD<\/b>, an open source debugging software largely used in ChibiStudio<\/a> since it is a reliable solution for debugging.<\/p>\n

The JTAG\/SWD connector<\/h3>\n

Joint Test Action Group<\/h4>\n

The JTAG<\/b> also know as Joint Test Action Group<\/i> is an electronics industry association founded in 1985 for developing standards for on-chip instrumentation in electronic design automation as an alternative to simulation tools. Today, the JTAG is a standard used by many semiconductor chip manufacturers which have extended it with commands to provide vendor-specific features.<\/p>\n

\"ARM<\/a>
Pin map of the ARM 20-pin connector.<\/figcaption><\/figure>\n

There are different JTAG connectors but almost everyone contains these PINs:<\/p>\n

    \n
  1. TDI, or Test Data In;<\/li>\n
  2. TDO, or Test Data Out;<\/li>\n
  3. TCK, or Test Clock;<\/li>\n
  4. TMS, or Test Mode Select;<\/li>\n
  5. TRST, or Test Reset which is optional.<\/li>\n<\/ol>\n

    As example in Fig.1 we can see a ARM 20-PIN JTAG connector<\/b> with the pin-map. The connector shown in figure is the same available on the STLink v2 and we are going to use it and certain PINs (the ones orange and azure) have a dual function.<\/p>\n

    ARM Serial Wire Debug<\/h4>\n

    The SWD<\/b> also know as Serial Wire Debug<\/i> is an interface developed by ARM<\/i> and is an alternative to JTAG for these packages with limited PINs. SWD uses a standard bi-directional wire protocol defined in the ARM Debug Interface v5<\/i>.
    \nSWD replaces the 5-pin JTAG port with a clock + single bi-directional data PIN having data rate up to 4 MB\/s at 50 MHz. Additional features could be achieved using one more PIN named TRACESWO. On JTAG devices with SWD capability:<\/p>\n

      \n
    1. TMS, is used as SWDIO;<\/li>\n
    2. TCK, is used as SWCLK;<\/li>\n
    3. TDO, is used as SWO.<\/li>\n<\/ol>\n