Digi JACKRABBIT BL1800 User Manual
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Jackrabbit (BL1800)
Editing the Program
Click on the
Edit
box on the task bar. This will set Dynamic C into the edit mode so that
you can change the program. Use the
Save as
choice on the
File
menu to save the file
with a new name so as not to change the demo program. Save the file as
MYTEST.C
. Now
change the number 25000 in the
for (..
statement to 10000. Then use the
F9
key to
recompile and run the program. The LED will start flashing, but it will flash much faster
than before because you have changed the loop counter terminal value from 25000 to
10000.
Watching Variables Dynamically
Go back to edit mode (select edit) and load the program
DEMOJR2.C
using the
File
menu
Open
command. This program is the same as the first program, except that a variable
k
has been added along with a statement to increment
k
each time around the endless loop.
The statement:
runwatch();
has been added. This is a debugging statement that makes it possible to view variables
while the program is running.
Use the
F9
key to compile and run
DEMOJR2.C
. Now type
<Ctrl-W>
to open the watch
window and add the watch expression
k
to the top of the list of watch expressions. Now
type
<Ctrl-U>
. Each time you type
<Ctrl-U>
, you will see the current value of
k
, which is
incrementing about 5 times a second.
As an experiment add another expression to the watch window:
k*5
Then type
<Ctrl-U>
several times to observe the watch expressions
k
and
k*5
.
Summary of Features
So far you have practiced using the following features of Dynamic C.
•
Loading, compiling and running a program. When you load a program it appears in an
edit window. You can compile by selecting
Compile
on the task bar or from the
Compile
menu. When you compile the program, it is compiled into machine language
and downloaded to the target over the serial port. The execution proceeds to the first
statement of main where it pauses, waiting for you to command the program to run,
which you can do with the
F9
key or by selecting
Run
on the
Run
menu. If want to
compile and start the program running with one keystroke, use
F9
, the run command. If
the program is not already compiled, the run command will compile it first.
•
Single-stepping. This is done with the
F8
key. The
F7
key can also be used for single-
stepping. If the
F7
key is used, then descent into subroutines will take place. With the
F8
key the subroutine is executed at full speed when the statement that calls it is
stepped over.