B. instruction set – EMC EM78612 User Manual

Page 34

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EM78612

Universal Serial Bus Microcontroller

32

•••

Product Specification(V1.0) 03.22.2006

(This specification is subject to change without further notice)

B. Instruction Set

Each instruction in the instruction set is a 11-bit word divided into an OP code and one
or more operands. All instructions are executed within one single instruction cycle
(consisting of 2 oscillator periods), unless the program counter is changed by-

(a) Executing the instruction "MOV R2,A", "ADD R2,A", "TBL", or any other instructions
that write to R2 (e.g. "SUB R2,A", "BS R2,6", "CLR R2",

⋅⋅⋅⋅

).

(b) execute CALL, RET, RETI, RETL, JMP, Conditional skip (JBS, JBC, JZ, JZA, DJZ,
DJZA) which were tested to be true.

Under these cases, the execution takes two instruction cycles.

In addition, the instruction set has the following features:

(1). Every bit of any register can be set, cleared, or tested directly.

(2). The I/O register can be regarded as general register. That is, the same instruction
can operate on I/O register.

The symbol "R" represents a register designator that specifies which one of the registers (including operational

registers and general purpose registers) is to be utilized by the instruction. Bits 6 and 7 in R4 determine the selected

register bank. "b" represents a bit field designator that selects the value for the bit located in the register "R" and

affects operation. "k" represents an 8 or 10-bit constant or literal value.

INSTRUCTION BINARY

HEX

MNEMONIC

OPERATION

STATUS AFFECTED

0 0000 0000 0000

0000

NOP

No Operation

None

0 0000 0000 0001

0001

DAA

Decimal Adjust A

C

0 0000 0000 0010

0002

CONTW

A

CONT

None

0 0000 0000 0011

0003

SLEP

0

WDT, Stop oscillator

T,P

0 0000 0000 0100

0004

WDTC

0

WDT

T,P

0 0000 0000 rrrr

000r

IOW R

A

IOCR

None <Note1>

0 0000 0001 0000

0010

ENI

Enable Interrupt

None

0 0000 0001 0001

0011

DISI

Disable Interrupt

None

0 0000 0001 0010

0012

RET

[Top of Stack]

PC

None

0 0000 0001 0011

0013

RETI

[Top of Stack]

PC,

Enable Interrupt

None

0 0000 0001 0100

0014

CONTR

CONT

A

None

0 0000 0001 rrrr

001r

IOR R

IOCR

A

None <Note1>

0 0000 0010 0000

0020

TBL

R2+A

R2,

Bits 8~9 of R2 unchanged

Z,C,DC

0 0000 01rr rrrr

00rr

MOV R,A

A

R

None

0 0000 1000 0000

0080

CLRA

0

A

Z

0 0000 11rr rrrr

00rr

CLR R

0

R

Z

0 0001 00rr rrrr

01rr

SUB A,R

R-A

A

Z,C,DC

0 0001 01rr rrrr

01rr

SUB R,A

R-A

R

Z,C,DC

0 0001 10rr rrrr

01rr

DECA R

R-1

A

Z

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