Module 02: Hardware-Accelerated Precision Timing

🧠 The Evolution

Project 01 used software delay loops which were blocking and non-deterministic. Project 02 implements a Global Heartbeat using the ARM SysTick timer.

⚙️ Technical Specs

• Clock Source: MSI @ 4MHz.
• Interrupt Frequency: 1000Hz (1ms).
• Control Register: 0x7 (Processor Clock, Exception Enable, Counter Enable).

🚀 Key Learning: The volatile Keyword

The ms_ticks variable is shared between the Background (Interrupt Context) and the Foreground (Main Loop). Declaring it as volatile prevents the compiler from optimizing out “redundant” reads, ensuring the delay_ms() function always sees the most recent tick count.