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Step 4: Add Application Code to the Project

Last modified by Microchip on 2026/06/26 07:40

Add Application Code to the Project

Once the project is generated, open the main.c file and declare the following variables outside the main() ​function.

/* Global variables stored in SRAM */
volatile uint32_t sram_global = 0x1234;
const uint32_t flash_global = 0x5678;

Global variables stored in SRAM

Add the following code inside the main() function and outside the while loop.

SysTick->CTRL |= SysTick_CTRL_ENABLE_Msk;

This line enables the SysTick timer in an Arm®-based microcontroller. SysTick->CTRL accesses the control register of the SysTick peripheral. The |= (OR) operator sets only the ENABLE bit (SysTick_CTRL_ENABLE_Msk) to 1 while preserving all other configuration bits. This is a safe way to start the timer without affecting existing settings.

Add the following lines of code inside the while loop.

/* Increment SRAM variables */
sram_global++;
/* Toggle User LED (GPIO Peripheral) */
LED_Toggle();
/* --- BREAKPOINT HERE --- */
__asm("nop");

Initialize all Harmony modules

  • SysTick->CTRL |= SysTick_CTRL_ENABLE_Msk; enables the SysTick timer, demonstrating system control space.
  • sram_global++; increments a variable stored in SRAM, showing normal memory access by the CPU.
  • LED_Toggle(); changes the state of the GPIO‑connected LED, demonstrating peripheral control.
  • __asm("nop"); is a no‑operation assembly instruction placed intentionally so a debugger breakpoint can pause program execution at this point.

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