EM73982 Просмотр технического описания (PDF) - ELAN Microelectronics

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EM73982

4-BIT MICROCONTROLLER

ELAN Microelectronics 

EM73982

4-BIT MICROCONTROLLER

Symbol

Pin-type

P8.1(TRGB)/WAKEUPB I/O-L

P8.3(TRGA)/WAKEUPD

VO

SOUND

COM0~COM7

SEG0~SEG39

TEST

Function

2-bit bidirection I/O port with time/counter A,B external input and Sleep

/Hold releasing function

mask option :

wakeup enable, push-pull

wakeup disable, push-pull

wakeup disable, open-drain

Built-in Speech synthesizer analog signal output

Built-in sound effect output

LCD common output pins

LCD segment output pins

Test pin must be floating

FUNCTION DESCRIPTIONS

ACCUMULATOR

Accumulator is a 4-bit data register for temporary data. For the arithematic, logic and comparative opertion

.., ACC plays a role which holds the source data and result.

FLAGS

There are three kinds of flag, CF (Carry flag), ZF (Zero flag), SF (Status flag), these 3 1-bit flags are affected

by the arithematic, logic and comparative .... operation.

All flags will be put into stack when an interrupt subroutine is served, and the flags will be restored after

RTI instruction executed.

(1) Carry Flag ( CF )

The carry flag is affected by following operation:

a. Addition : CF as a carry out indicator, when the addition operation has a carry-out, CF will be "1",

in another word, if the operation has no carry-out, CF will be "0".

b. Subtraction : CF as a borrow-in indicator, when the subtraction operation must has a borrow, in the CF

will be "0", in another word, if no borrow-in, CF will be "1".

c. Comparision: CF is as a borrow-in indicator for Comparision operation as the same as subtraction

operation.

d. Rotation: CF shifts into the empty bit of accumulator for the rotation and holds the shift out data after

rotation.

e. CF test instruction : For TFCFC instruction, the content of CF sends into SF then clear itself "0".

For TTSFC instruction, the content of CF sends into SF then set itself "1".

(2) Zero Flag ( ZF )

ZF is affected by the result of ALU, if the ALU operation generate a "0" result, the ZF will be "1",

otherwise, the ZF will be "0".

* This specification are subject to be changed without notice.

11.30.2001 3

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