STC89LE53RC datasheet(154/165 Pages) STC

Part #	STC89LE53RC

Description	Enhanced 80C51 Central Processing Unit ,6T or 12T per machine cycle

PDF	165 Pages

Scroll/Zoom	100%

Manufacturer	STC [STCmicro Technology Co,.Ltd]

Direct Link	http://www.stcmicro.com/

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Control Flow Operations

The conditional assembly of section of code is provided by ASM51's control flow macro definition. The format is

%IF (expression) THEN (balanced_text)

[ELSE

(balanced_text)] FI

For example,

INTRENAL

EQU

;1 = 8051 SERIAL I/O DRIVERS

;0 = 8251 SERIAL I/O DRIVERS

%IF (INTERNAL) THEN

(INCHAR:

;8051 DRIVERS

OUTCHR:

) ELSE

(INCHAR:

;8251 DRIVERS

OUTCHR:

)

In this example, the symbol INTERNAL is given the value 1 to select I/O subroutines for the 8051's serial port,

or the value 0 to select I/O subroutines for an external UART, in this case the 8251. The IF macro causes ASM51

to assemble one set of drivers and skip over the other. Elsewhere in the program, the INCHAR and OUTCHR

subroutines are used without consideration for the particular hardware configuration. As long as the program as

assembled with the correct value for INTERNAL, the correct subroutine is executed.

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STC89LE53RC Datasheet(PDF) 154 Page - STCmicro Technology Co,.Ltd