1. The CPU12 Microprocessor Core
Lecture L2.1

2. Reference S12CPUV2 Reference Manual S12CPUV2.pdf (in .zip file)
Print out Appendix A – Instruction Reference
It will answer all questions concerning HCS12
instructions and addressing modes

3. Introducing the CPU12 The CPU12 Registers CPU12 Addressing Modes
CPU12 Instructions

4. The 68HC12 Registers

5. Condition Code Register

6. The 68HC12 Accumulators A c c u m u l a t o r A A B A c c u m u l a tD D

11. Index Registers, X and Y I n d e x r e g i s t e r X X I n d e x r e g

13. S t a c k P o i n t e r S P
Stack Pointer, SP

15. Introducing the CPU12 The CPU12 Registers CPU12 Addressing Modes
CPU12 Instructions

18. Pre-decrement indexed addressing

19. Using X as a stack pointer for a data stack
LDY 2,X+ will pop $1234 into Y

20. MOVW 0,X,2,-X

21. LDD 0,X MOVW 2,X,0,X STD 2,X

22. MOVW 2,X,2,-X

23. Introducing the CPU12 The CPU12 Registers CPU12 Addressing Modes
CPU12 Instructions

37. Load Accumulator A 1: ; LDAA Addressing Modes 2: =00004000 ORG $4000
5: B LDAA $5678
6: A LDAA 3,X
7: A6 E LDAA ,Y
8: C A6 F LDAA $1234,SP
9: A6 E LDAA [D,X]
10: A6 EB LDAA [$2345,Y]

38. 1: ; LDAA Addressing Modes
2: = ORG $4000
3: LDAA #$35
4: A LDAA $A3
5: B LDAA $5678
6: A LDAA 3,X
7: A6 E LDAA ,Y
8: C A6 F LDAA $1234,SP
9: A6 E LDAA [D,X]
10: A6 EB LDAA [$2345,Y]
200 = $C8 = bit =
2’s comp = = $138
= $E9

39. 11110010 = $F2 1: ; LDAA Addressing Modes 2: =00004000 ORG $4000
4: A LDAA $A3
5: B LDAA $5678
6: A LDAA 3,X
7: A6 E LDAA ,Y
8: C A6 F LDAA $1234,SP
9: A6 E LDAA [D,X]
10: A6 EB LDAA [$2345,Y]
= $F2

40. 11100111 = $E7 1: ; LDAA Addressing Modes 2: =00004000 ORG $4000
4: A LDAA $A3
5: B LDAA $5678
6: A LDAA 3,X
7: A6 E LDAA ,Y
8: C A6 F LDAA $1234,SP
9: A6 E LDAA [D,X]
10: A6 EB LDAA [$2345,Y]
= $E7

41. 11101011 = $EB 1: ; LDAA Addressing Modes 2: =00004000 ORG $4000
4: A LDAA $A3
5: B LDAA $5678
6: A LDAA 3,X
7: A6 E LDAA ,Y
8: C A6 F LDAA $1234,SP
9: A6 E LDAA [D,X]
10: A6 EB LDAA [$2345,Y]
= $EB