HCS12 Microcontroller/CodeWarrior LED Blink Tutorial — Delay Loop Explained (50 Hz on PORTB)

Full walkthrough of an HCS12 assembly language solution that blinks an LED connected to PORTB bit 5 (PB5) at a 50 Hz frequency, assuming a 24 MHz bus clock. This is a common embedded systems / microcontrollers course assignment using the HCS12 (Freescale/NXP). If you're working through a similar "blink an LED at X Hz" problem, this video walks through the complete process from the timing calculations to the working assembly code. Timestamps: 0:00 – Problem statement (blink LED on PORTB bit 5 @ 50 Hz, 24 MHz bus clock) 0:40 – Calculating the period (T = 1/f) and drawing the waveform 1:30 – Flowchart 2:20 – Converting time to clock cycles (24 MHz → cycles needed for 0.01 sec) 2:55 – Writing the delay loop skeleton (LDY, DEY, BNE) 3:25 – Checking BNE/DEY cycle timing in the HCS12 instruction reference 4:10 – Solving for the loop count and checking the 16-bit register limit (65,535) 5:38 – Setting up the project in CodeWarrior (main.asm) 6:20 – Writing the main program: setting PORTB as output and turning the LED ON/OFF 8:37 – Writing the complete Delay subroutine 9:10 – Reviewing the finished assembly code 10:10 – Loading the program into the True-Time Simulator/debugger 10:30 – Setting up the LED in the Visualization Tool (port, bit, colors) 12:30 – Running the simulation — LED blinking at 50 Hz #HCS12 #EmbeddedSystems #AssemblyLanguage #Microcontroller #CodeWarrior