1. MICRO-CONTROLLER MOTOROLA HCS12 Addressing Modes Mechatronics Department Faculty of Engineering Ain Shams Univeristy

2. HCS12 Addressing Modes HCS12 instruction set can be categorized according to the type of operand used for every instruction.  Immediate Addressing.  Direct/Extended Addressing.  Indexed Addressing.  Inherent Addressing.  Relative Addressing.

3. HCS12 Programmer’s model  Accumulator (Operand Register).  Index Registers X&Y (Keeps addresses for specific instructions using addresses as operands).  Stack Pointer (Keeps track of program stack in the Ram).  Program Counter (Keeps track of the program script). AB X Y SP PC

4. $ 5000 $ 5001Op-Code $ 5002Operand $ 5003 $ 5004 $ 5005 Instruction Set Example  ldaa#$64;  ldaa#$6464; Operand

5. Immediate Addressing  ldaa#$64; AB X Y SP PC #$64

6. Direct Addressing  ldaa$64; AB X Y SP PC $ 0063 …… $ 0064 $FF $ 0065 …… $64 $FF

7. Extended Addressing  ldd$1234; D X Y SP PC $ 1233 …… $ 1234 $FF $ 1235 $FF $1234 $FF

8. Indexed Addressing  ldaa!1,x; AB X $0064 Y SP PC $ 0064 …… $ 0065 $FF $ 0066 …… $0064 $FF +1 $0065

9. Indexed Pre-decrement Addressing  ldaa!1,-x; AB X $0065 Y SP PC $ 0064 $FF $ 0065 …… $ 0066 …… $0064 $FF $0065 $0064 $0064

10. Indexed Post-increment Addressing  ldaa!1,x+; AB X $0064 Y SP PC $ 0064 $FF $ 0065 …… $ 0066 …… $0064 $FF +1 $0065 $0065 $0064

11. Indexed Indirect Addressing  ldaa[!1,x]; AB X $0064 Y SP PC $ 0064 …… $ 0065 $00 $ 0066 $67 $ 0067 $FF $0064 $FF +1 $0065 $0067

12. Eng. Mohamed Mahmoud Hamdy Eng. Mostafa Ahmed Arafa Prepared by: