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Configure Startup Code

Typically, target programs require a startup-code to initialize the CPU to match the configuration of the hardware design. When creating a project, µVision adds the device specific CPU startup-code for most devices to the project.

The startup-code executes immediately upon RESET of the target system. It performs the following operations:

  1. Reserves memory and initializes the stack.
  2. Reserves memory for the heap.

A more flexible software concept, the Cortex Microcontroller Software Interface Standard - CMSIS, has been introduced with the Cortex device family.

µVision provides a Configuration Wizard that makes it easy to configure the device:

  1. Double click the startup_xxx.s (Startup) file. The file opens in the Editor Window. Two tabs are displayed at the bottom of the Editor: Text Editor and Configuration Wizard.

    Config Wizard

  2. Choose the Configuration Wizard tab.
  3. Click the Value field to change the content.


  • Startup files can have a file name matching the device family name.
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