Thanks for choose the 650E 8-bit Processor!

In this thread you will learn how to program this new and easy-to-use processor.(*)

• Pinout:

• Architecture:

• Specifications:

Data width: 8 bits    Instructions: 16
Clock rate: 2 Hz    Address width: 10 bits

• Registers:

    [  A   ] Accumulator
    [  B   ] B register
    [  C   ] C register
  [  P. C. ] Program Counter
    [Z] [C] Processor Status Flags

• Instruction architecture:

2 bytes per instruction.
    First Byte(Instruction, Register, Memory page)
    bit  7 6 5 4  3 2  1 0
         -------  ---  ---  (Respectively)
    Register selector:
    bit  3 2
    --------------------
         0 0 Register B
         0 1 Register C
         1 0 Direct Data
         1 1 Memory Access

    Second Byte(Direct Data/Memory Address)

*Note that it uses the less significant 2 bits from first byte to set the memory page location.
        %10101100, %01001011
                     --     --------
       Memory Page    Memory Address    (10 bits total for Full Memory Access)

• Fetching process:  (***)
  

If Fetch is ON....
Clock cycle 1: [Memory address IN] [Counter OUT]
                2: [Instruction decoder IN] [Memory page IN] [Register selector IN] [Memory OUT] [Counter INCREMENT]
                3: [Memory address IN] [Counter OUT]
                4: [Addres/Direct data Register IN] [Memory address IN] [Memory OUT]
                5: [Counter INCREMENT] [Fetch OFF] [Instruction EXECUTE]

• Instrucion Set:

0000- NOP: No OPeration. It is simply a void instruction cycle. It may be useful to let the processor        wait for other

devices operations like an I/O port.

0001- LDA: LoaD to Accumulator. Loads data stored wherever the Register Selector has... selected.

For instance: If bits 3 and 2 are 0 and 1 respesctively, Will load data from Register C.

0010- STA: STore Accumulator. Store data from accumulator to wherever the Register Selector               indicates. (*Data cannot be stored in Direct Data/Address Register)

0011- ADD: ADDs to accumulator a value stored wherever the Reg. Sel. indicates.

0100- SUB: SUBtracts from accumulator a value stored wherever the Reg. Sel. indicates.

0101- NOT: Inverts the accumulator.

0110- XOR: eXclusive OR. Logical exclusive OR the accumulator bits with data stored where Reg. Sel. indicates.

0111- ROL: ROtate Left. Shift bits in accumulator to the left. (The same as: Accumulator x2)

1000- CLC: CLear Carry flag.

1001- CLZ: CLear Zero flag.

1010- JMP: JuMP to memory address specified in bits 1 and 0, and the second byte. (Bits 3 & 2 must be always set)

1011- JIZ: Jump If Zero. Like JMP, but only if Zero flag is set. (**)

1100- JNZ: Jump if Not Zero. Like JMP, but only if Zero flag is not set. (**)

1101- JIC: Jump If Carry. Like JMP, but only if Carry flag is set. (**)

1110- JNC: Jump if Not Carry. Like JMP, but only if Carry flag is not set. (**)

1111- HLT: HaLT. Stop the clock(Does not Reset the chip).

Instruction examples:
    LDA #$0E ==> %0001 10 00, %00001110 (Load Accumulator with number 14 = $0E)
    STA $265 ==> %0010 11 10, %01100101 (Store Accumulator in Memory Address 613 = $265)
    SUB C    ==> %0100 01 00, %00000000 (Subtract data in Register C to Accumulator)
    JMP $23  ==> %1010 11 00, %00100011 (Jump in Program to Memory Address 35 = $23)

    (Prefixes: #=Direct Data (From program). $=Hexadecimal Number. %=Binary Number.)

Notes:
(* To understand this manual, you will need to already know binary system and basic logic gates)

(** Before check the zero/carry flag, you will need to perform a STA instruction for flag update) 

 

(*** You may need a proper memory to fit the 650E Fetching need)

Eliasdbr Semiconductors ©1986


//I hope you like my job! I will frequently see the saves comment if you want to report bugs or
//post you project made with this processor =D

Thank you very much guys!

 

@12Me21 You're right, but this ALU only has the Left Shift operation :( and I think there is no way to do right shift with other operations. If you could help me... I would be glad!

 

I'll do a revision to this Processor when I have enough sugestions!