Special Code Examples

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Button-Controlled LED Chaser with Direction Reversal

Objective: 8 LEDs chase from right to left. Press and hold a button to pause; release to reverse direction. Each press toggles direction.

Register Map:

Register	Purpose
R01	LED bitmask (initial 0x0001)
R02	Direction flag (0x0000 = left shift / right-to-left, 0x0001 = right shift / left-to-right)
R05	Delay value in seconds
R3E	Button state register (0x0000 = not pressed, 0x0001 = pressed)

Mnemonic Form

;=== Initialization ===
000  FZ    0001  0001  ; R01 = 1 (rightmost LED on)
001  FZ    0002  0000  ; R02 = 0 (direction: left shift = right-to-left)
002  FZ    0005  0001  ; R05 = 1 (1-second delay)

;=== Main Loop (line 003) ===
003  SS    0001  0000  ; Output R01 to LEDs
004  YS    0005  0001  ; Delay 1 second
005  JFZ   0000  003E  ; Copy R3E (button) to R00
006  TJZ   0800  0010  ; If R00 ≠ 0 (pressed), jump to pause 010
007  JFZ   0000  0002  ; Copy R02 (direction) to R00
008  TJZ   0700  000C  ; If R00 == 0 (left shift), jump to 00C

; Right shift branch (direction = 1, left-to-right)
009  XHYW  0101  0001  ; R01 circular right shift by 1
00A  ZY    0000  0003  ; Jump back to main loop 003

; Left shift branch (direction = 0, right-to-left)
00C  XHYW  1101  0001  ; R01 circular left shift by 1
00D  ZY    0000  0003  ; Jump back to main loop 003

;=== Pause (line 010) ===
010  SS    0001  0000  ; Output R01 (hold LED state)
011  YS    0005  0001  ; Delay
012  JFZ   0000  003E  ; Copy R3E to R00
013  TJZ   0700  0015  ; If R00 == 0 (released), jump to reverse 015
014  ZY    0000  0010  ; Otherwise keep waiting 010

;=== Reverse Direction (line 015) ===
015  JFZ   0000  0002  ; Copy R02 to R00
016  TJZ   0700  0019  ; If R00 == 0 (was left shift), jump to 019
; Was right shift → change to left shift
017  FZ    0002  0000  ; R02 = 0 (left shift)
018  ZY    0000  0003  ; Jump back to main loop 003
; Was left shift → change to right shift (line 019)
019  FZ    0002  0001  ; R02 = 1 (right shift)
01A  ZY    0000  0003  ; Jump back to main loop 003

Instruction Form

;=== Initialization ===
000  10  0001  0001  ; R01 = 1 (rightmost LED on)
001  10  0002  0000  ; R02 = 0 (direction: left shift = right-to-left)
002  10  0005  0001  ; R05 = 1 (1-second delay)

;=== Main Loop (line 003) ===
003  13  0001  0000  ; Output R01 to LEDs
004  02  0005  0001  ; Delay 1 second
005  11  0000  003E  ; Copy R3E (button) to R00
006  0A  0800  0010  ; If R00 ≠ 0 (pressed), jump to pause 010
007  11  0000  0002  ; Copy R02 (direction) to R00
008  0A  0700  000C  ; If R00 == 0 (left shift), jump to 00C

; Right shift branch (direction = 1, left-to-right)
009  15  0101  0001  ; R01 circular right shift by 1
00A  0E  0000  0003  ; Jump back to main loop 003

; Left shift branch (direction = 0, right-to-left)
00C  15  1101  0001  ; R01 circular left shift by 1
00D  0E  0000  0003  ; Jump back to main loop 003

;=== Pause (line 010) ===
010  13  0001  0000  ; Output R01 (hold LED state)
011  02  0005  0001  ; Delay
012  11  0000  003E  ; Copy R3E to R00
013  0A  0700  0015  ; If R00 == 0 (released), jump to reverse 015
014  0E  0000  0010  ; Otherwise keep waiting 010

;=== Reverse Direction (line 015) ===
015  11  0000  0002  ; Copy R02 to R00
016  0A  0700  0019  ; If R00 == 0 (was left shift), jump to 019
; Was right shift → change to left shift
017  10  0002  0000  ; R02 = 0 (left shift)
018  0E  0000  0003  ; Jump back to main loop 003
; Was left shift → change to right shift (line 019)
019  10  0002  0001  ; R02 = 1 (right shift)
01A  0E  0000  0003  ; Jump back to main loop 003

Behavior Summary

Action	Effect
Normal run	8 LEDs chase from right to left (circular left shift)
Press and hold button	Chaser pauses immediately, only current LED stays on
Release button	Direction reverses — right-to-left becomes left-to-right, and vice versa
Press again	Direction reverses again, toggling repeatedly