© 1994 Microchip Technology Inc.

DS00584A-page 3

PICMASTER Support of Microsoft Windows DDE

5

.

; Code Initialization

CLRW

; Place 0 into W register

OPTION

Port_B

; Make all Port B pins outputs to feed variable state data to logic inputs

.

; Use MOVWF DDRB instruction in place of OPTION for 17C42

.

.

; Place where Speed variable is modified and needs to be traced

MOVF

SPEED,W

; Place Speed value into W register

MOVWF

Port_B

; Place value into Port B

.

; Execute normal instruction

.T..

.

; Trace second instruction after Port B move to capture current value

0

50

100

150

200

250

300

1

1121

31

415161

7181

91

Series1

Method 2: Using the Logic Analyzer external inputs (PIC16C5X, PIC16CXX, PIC17C42).

Connect the eight logic analyzer inputs TRC<7:0> to a currently unused digital output port of the PIC16/17. Set the port

direction of this port to OUTPUT and when you want to look at a value, simply move the value to the port and set the trace

bit on the second instruction following the move instruction. The following example shows this:

FIGURE 1: EXCEL SPREADSHEET EXAMPLE OF REAL-TIME PSEUDO-SINE WAVE GENERATOR

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