Make Electronics

Experiment 34: Hardware Meets Software

300 Chapter 5

In from

Computer

Out to

Computer

Negative

Power

Figure 5-132. Correct wiring of the socket is essential. When soldering wires to
the lower terminals, make sure that you attach the wires to both of the terminals
in each pair.

Figure 5-133. The breadboard version of the test

schematic, with the plug of the USB download

cable inserted in the socket on the board. The

PICAXE chip can now receive a downloaded pro-

gram, and will immediately start to execute it.

Verifying   the Connection

Follow these steps carefully every time you want to program or reprogram

your PICAXE chip:

1. Insert the USB plug of your PICAXE cable into the same USB port that you
   used before.


2. Start the Programming Editor (or AXEpad if you are using a Mac OS or
   Linux).


3. In the Programming Editor, select View→Options to verify that the editor
   is using the right COM port and is expecting the 08M PICAXE chip.


4. Plug the stereo plug on the free end of the USB cable into the stereo sock-
   et that is now wired into your breadboard. See Figures 5-133 and 5-134.


5. Check your wiring, and then connect your power supply to the breadboard.


6. Click the button labeled “program” in the Program Editor window to tell
   the software to look for the PICAXE.

What    If  It  Doesn’t Work?   

The first thing to do is pull out the plug of the USB cable from the PICAXE

breadboard, leaving the other end of the cable attached to your computer. Set

your multimeter to measure DC volts, and attach its probes to sections b and c

of the plug. See Figure 5-135. Now click the “program” button again, and your

meter should show 5 volts briefly coming out of your computer to the plug on

the end of the cable.

Figure 5-134. After the program has been
downloaded, the plug can be removed,
and the program will continue to run,
causing the LED to continue flashing.