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How do i program a PICAXE-28X1 microcontroller chip using serial cable.

Well am new to making robots.am using a PICAXE-28X1 microcontroller chip with a picaxe 28 starter board.when I connect my board to computer using serial cable it is not responding. Am using a picaxe programming editor for programing.when I connect my board to a 4.8V my pic nd L293D is getting hot. Can anyone please help me with this. I really wanted to make a robot. My pic is pre-programmed with bootstrap loader program..Well am new to making robots.

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at last i programmed it.. :)

I could not help but notice you are using (2) 9v battery snaps plugged into each other. By doing so you have reversed your polarity (as described by King and Bird above).

Now, all you gotta do is fix this, then think very very happy thoughts that you did not fry your chip already.

that occurred after you seem to have left, "we" think you may have the battery leads reversed. You could check this easily. First remove your chips from their sockets. Next check the voltage at the input to the board with a voltmeter by putting the red lead on the + input on the board, and, the black lead on the - input on the board. Your voltage should be positive. If it is not, you need to reverse the polarity at your battery.

Looking at the board that way, orientation that is, the white 3 pin molex connector hook up is

top pin 0v

middle pin serial in

bottom pin serial out


Check to see that you are not connecting the batteries backwards.  I did this and the LD293 got hot enough to burn the tip of my finger in seconds.

This can be easier to mess up than you might think.  Everyone knows 'red to red' and 'black to black', but....

I soldered a 9-volt battery clip to the wires of my 4-AA battery pack and then snapped it to the one on the board.

The catch is that to make them mate you turn one of the clips around, which means I got it ...EXACTLY... backwards.

Once I realized my mistake, I switched the wires around between my battery back and the 9-volt clip and all was well.

Be sure to check you have positive and negative connected right, if not I promise it will make the LD293D very hot.

page 44 of the first manual shows the serial pin out Paul

I would put $100 on the fact that one of your motor connections (A/B) are bridged with solder.

That said, we will not know for sure until we get some pics and more info. 


In terms of your serial cable, you ask, "should I connect anything to my serial cable"...  What do you mean by this exactly? One end can only go one place on your 28x board, and the other end can only go one place on your computer. What else were you planning on connecting to this cable?