COP880C datasheet(18/31 Pages) NSC

18 / 31 page

Memory Map (Continued)

Address

Contents

B Register

Reading unused memory locations below 7FH will return all

ones. Reading other unused memory locations will return

undefined data.

Instruction Set

Registers

8-bit Accumulator register

8-bit Address register

8-bit Stack pointer register

15-bit Program counter register

upper 7 bits of PC

lower 8 bits of PC

1-bit of PSW register for carry

Half Carry

GIE 1-bit of PSW register for global interrupt enable

Symbols

[B]

Memory indirectly addressed by B register

[X]

Memory indirectly addressed by X register

Mem

Direct address memory or [B]

MemI Direct address memory or [B] or Immediate data

Imm

8-bit Immediate data

Reg

and SP)

Bit

Bit number (0 to 7)

←

Loaded with

↔

Exchanged with

Instruction Set

ADD

add

A ← A + MemI

ADC

add with carry

A ← A+MemI+C,C ← Carry

HC ← Half Carry

SUBC

subtract with carry

A ← A + MemI +C, C ← Carry

HC ← Half Carry

AND

Logical AND

A ← A and MemI

Logical OR

A ← A or MemI

XOR

Logical Exclusive-OR

A ← A xor MemI

IFEQ

IF equal

Compare A and MemI, Do next if A = MemI

IFGT

IF greater than

Compare A and MemI, Do next if A > MemI

IFBNE

IF B not equal

Do next if lower 4 bits of B

≠ Imm

DRSZ

Decrement Reg. ,skip if zero

Reg ← Reg − 1, skip if Reg goes to 0

SBIT

Set bit

1 to bit,

Mem (bit= 0 to 7 immediate)

RBIT

Reset bit

0 to bit,

Mem

IFBIT

If bit

If bit,

Mem is true, do next instr.

Exchange A with memory

↔ Mem

LD A

Load A with memory

A ← MemI

LD mem

Load Direct memory Immed.

Mem ← Imm

LD Reg

Load Register memory Immed.

Reg ← Imm

Exchange A with memory [B]

↔ [B]

(B ← B±1)

Exchange A with memory [X]

↔ [X]

(X ← X±1)

LD A

Load A with memory [B]

A ← [B]

(B ← B±1)

LD A

Load A with memory [X]

A ← [X]

(X ← X±1)

LD M

Load Memory Immediate

[B] ← Imm (B ← B±1)

CLRA

Clear A

A ← 0

INCA

Increment A

A ← A+1

DECA

Decrement A

A ← A−1

LAID

Load A indirect from ROM

A ← ROM(PU,A)

DCORA

DECIMAL CORRECT A

A ← BCD correction (follows ADC, SUBC)

RRCA

ROTATE A RIGHT THRU C

C → A7 → … → A0 → C

COP880C Datasheet(PDF) 18 Page - National Semiconductor (TI)

COP880C Datasheet(HTML) 18 Page - National Semiconductor (TI)

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