Let's Make Robots!

Breadboard Basics II (Add PICAXE)


Time to add PICAXE to the board.

This requires:

  1. A breadboard
  2. 5volt power source
  3. PICAXE 28x1 chip
  4. Stereo Socket
  5. USB or Seriel Transfer cable
  6. 4k7 ohm resistor
  7. 330 ohm resistor
  8. 22k ohm resistor
  9. 10k ohm resistor
  10. LED
  11. Wire

Note how there are 5 pins on the socket, but you only really use 3 (serial out, serial in, and ground). The 2 sets of 2 pins get tied together and then they get tied to each other via a 10k ohm resistor. When looking above the socket as shown in the picture the left 2 pins go to ground, the right 2 pins go to serial in via a 22k resistor, then the last pin which is near the opening of the socket goes to serial out.

 

Basically all this did was help me to learn how to hook up the chip and a stereo socket to a breadboard and get basic output (blinking LED). Hopefully it will help someone else too! Lots of pics to follow so you can see how it is connected. The code follows the pictures.

For help on how to hook up the stereo socket or for what pins do what on the chip click here.

http://www.rev-ed.co.uk/docs/AXE001_pinout.pdf

 socket.JPG

100_0984.JPG100_0985.JPG

100_0986.JPG

100_0987.JPG

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Symbol LED = 0

AGAIN:
HIGH LED
pause 1000

LOW LED
pause 1000

GOTO AGAIN

END

 

The code assumes you are using output 0 for the LED. If you can't get the editor to connect to your chip make sure you have the com port setting correct.

  1. Click START (lower left corner of your screen)
  2. Right click My Computer
  3. Click Properties
  4. Click Hardware Tab
  5. Click Device Manager Button
  6. Expand the Ports (COM & LPT)
  7. It should have an item called AXE027 PICAXE USB (COMX) X is your COM Port Number
  8. In the editor go to View->Options
  9. Click Seriel Port tab
  10. Select the Com Port you found in step 7 and click OK
  11. Try to transfer the code again.
  12. If it still doesn't work make sure your batteries are charged and connected to the breadboard.
  13. If it STILL doesn't work take a picture that shows the connections and post

For larger more detailed images click here. No fair making fun of my dirty coffee table.

 

Updated to include new pics using resistors, which should have been there in the first place.

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can u help me to connect my usc cable to the picaxe, coz i have tried everything it doesnt work. im doing the test program, bt the led doesnt oscillate.

 

plzz help me tanx.

i just tried this some days ago, not following this post's instruction though, as i didn't know about it. I can't get it to work and don't really know how. I've set up the enhanced download circuit. I'll try with the reset switch tomorrow
I havent ever used a reset switch. I just unplug the battery because I'm lazy.

What chip are you using here is the datasheet on this stereo socket that shows which pin connects to the PICAXE.

 http://www.rev-ed.co.uk/docs/AXE001_pinout.pdf

If you need a more detailed response please be more detailed in how you have it connected. Post some photos or a drawing showing pics on the stereo socket and how they are connected to the chip. Also post which chip you are using 28x, 8m, etc.

it's just an additional tool to help prototype. I have one and use it for multiple bb's that have different setups.

Who knows. I never had any problems getting the stereo socket to fit and stay in place. I was surprised at how easily it popped in. I eventually soldered wires onto it so it didn't take up 5 spots on my breadboard. When I got my motor driver, picaxe chip, and servo installed it took up a lot of room!

So Sparkfun can make money?

Jokes aside, I did the same in the beginning. There are some plastic tabs on the socket that I had to remove to make it fit better. Later, I soldered the required resistors directly onto the socket and added some longer pins. 

I finally got my Picaxe28X1 and I am trying to get this, the equivelent of a hello world, working. I was reading the datasheets and manuals for the picaxe28 and 28X1 and it tells to wire differently then you have shown here. their method has no connection between the ground and the serial circuit. the one shown above connects pin 8 to the ground as well as one of the connectors comming form the computer.

Is there a difference? is it a big difference and which is better.

 

UPDATE: I think I got it so never mind but if anyone want s to answer it anyway feel free. 

Nice work. Does the Picaxe not need an external resonator or oscillator crystal? I've been interested in this kind of thing, finding the minimum number of components you need for a microcontroller, to shrink it down once you're building you project. But at least with the Arduino, it looks like you always need at least a voltage regulator for power and resonator or crystal to tell it how fast to run. I guess maybe the Picaxe has that internally?

Dan

Like fritz! stated. Minimal setup is listed for every picaxe in manual1.

Basicly: if you're done programming the picaxe and don't need the serial connetion, only the pulldown resistor for the serial (10K) in and the pull-up resistor for the reset button (4.7K) are needed. The chips without a reset pin don't need theresistor off course.

The external resonator or crystal is optional for all models. They all have an internal 4Mhz resonator, but that one is not very accurate. (I hooked up two 08M chips with an LED flashing on and off every second and they get visibly out of sync in about 10 seconds!)

If you do have an external resonator, like on the standard the 28X1 board -> USE THE setfreq em4 command in the init routine. Otherwise the program will ignore the external resonator and default to the internal resonator.

BTW: The picaxe breadboard adapter is very handy. It is just a serial connetor with the proper resistors and a few pins to stick it on the board. I use it to program multiple picaxe chips on one breadboard without creating a spaghetti of resistors and sockets. (http://194.201.138.187/epages/Store.storefront/?ObjectPath=/Shops/Store.TechSupplies/Products/AXE029)