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Programming a Picaxe with a Arduino FTDI Cable

programs a picaxe

I am going to tell you how to use the same cable you use to program your Arduino with to program a Picaxe. I am sure this could also be used the other way around too. I wish i did this before i paid for the Picaxe FTDI adapter. 

Why do we use a hex inverter to program a Picaxe with the Arduino cable?

Well the signals coming from the Arduino FTDI cable are inverted from that off the Picaxe FTDI cable. That means they are the opposite. If you tried to program a Picaxe with the Arduino cable it wouldnt work because when the Arduino cable sends a 0 the Picaxe really needs a 1 and when the Arduino sends a 1 the Picaxe really needs a 0. So we use a hex inverter to inverter the output to the opposite so we can program the Picaxe. This walkthrough showed that you can inverte the signals by reprogramming the FTDI cable, but i did not want to do that every time i switched in between a Picaxe and Arduino. 

The parts I  used:

Resources we will be using:

What we use in the hex inverter data sheet is the connection diagram on page 1. On the picaxe manual we use the diagram of the download circuit on page 7 as a reference. 


The hex inverter takes 5v. Wire 5v to pin 14 and 0v to pin 7. Notice the notch, that is the front of the chip (you should know this by now) and the circle on the chip indicates pin 1. I used a batter to power this circuit because i could not upload the program using the FTDI power. It may work for you but i suggest just going ahead and using batteries to supply the power. I used 4 1.2v batteries. 

Pin 1 of the hex inverter is where the TX from your Arduino FTDI cable gets connected to. The TX is the orange wire on the Arduino FTDI cable. The inverted signal then comes out of pin 2. So pin 2 will needs to be connected to the audio jack. Refer to picaxe's manual. The diagram of the above view shows that the Serial in  of the picaxe is connected to the bottom right pin of the audio jack (above view remember. Picaxe manual page 7). So wire pin 2 of the hex inverter to the bottom right pin of the audio jack. 

Next we can see that Serial out from the picaxe is wired to the top middle pin of the audio jack. So next wire the top middle pin of the audio jack to pin 3 of the hex inverter. Then wire pin 4 of the hex inverter to the FTDI RX. The FTDI RX is the yellow wire on the FTDI cable. 

Finally connect all grounds in the circuit. The ground from your battery, the ground from the FTDI cable and the ground from the audio jack which is the bottom left pin.

Ok you are ready to program. Use a audio cable adapter to plug in a Picaxe board to your newly made adapter. Now plug in the FTDI cable and program. Make sure everything is powered on. 

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Will this work on any picaxe chip. I've got one with 12F629    I/SN0609   5HJ written on it. It's on a flashing badge kit an receives input from a normal 3.5mm headphone cable.


Thanks in advance!

Nice work, Dude!  Do you know of any reason to NOT use this to invert the signals?

This is one neat trick patrick...cool,

i have also a usb FTDI ,  the cable will program both pic&ard but the pain being having to revert it back and forth by the software ding.......

Q:- Could you program a 08M to do the invertion for you - (im new to pic too) its just an idea no clue if it would work.......

Sounds like a interesting idea. I would wonder if you run into speed issues using a Picaxe to invert the signals. You will probably get an answer but not by me because i have no clue ;) I also saw that using some transistors and resistors you might be able to accomplish the same thing that the hex inverter does. 

Thanks for sharing this! I recently got my hand on a few PicAXE 08M's and wanted to play with them without having to buy another piece of hardware to program them.

So I adapted this idea, but I did not have any hex inverter, so build two NOT-gates (basically the circuit on the bottom of the page here: http://www.kpsec.freeuk.com/trancirc.htm  I went for 1.48K and 8K resistors and P2N2 222A transistors.)

Also, I just wired an audio cable with an audio plug directly to the board:

(Note that this image was taken before I realised I the wires going to the audio cable were flipped. :])

I have to remove power, power, reconnect the FDTI adapter and hit "Program" a few times, but after a few attempts it succesfully uploads the basic program to the chip -- and I got a nice blinking red LED as a result. ;-)

(Unsure why it needs a few times before it sees it, but this'll do for now.)

Yeah, I asked the same thing...

The kid's friggin' 16!  Yup, 16.

I have the same age  :P

Just a simple question.

How old are you?

You have been on fire lately!



P.s. I swear to God, if you don't get a full scholarship to university from all this stuff...

No kidding. Pat, when it comes time for college, see if letters of recommendation from LMR will be useful ;)