Sparkfun Picaxe Download Device

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kewakl

Senior Member
Sparkfun has a programming board ->>
NOT SURE HOW TO MAKE AN INTO A [LINK]:mad:

for programming Picaxe chips. $14.95 USD -- three-fifths the price of the axe027 (USD $25.95)
This is NOT a cable like axe027, but a board that has the FTDI chip.
Still a miniUSB CABLE is required.
The site says for WINDOWS/LINUX with rx/tx LEDs .
If a 5V line is available, then GREAT!! I'm sure that I can remove the *stereo socket* and get access to the USB 5V line.
 
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boriz

Senior Member
From Sparc, sorry, I mean SparkFun (I always get them confused) :

"Why buy this board? Because blinky things are better."

:)
 
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womai

Senior Member
I'm not quite sure why they made the serial side a stereo connector. That's the PC side, not the Picaxe side, so to use it with a Picaxe not only will you need a USB cable (chances are everybody already has a suitable one from his/her mp3 player or digital camera), but also needs to buy/build/find a stereo-to-pin-header cable. Looks unnecessarily complicated to me. Why didn't they just put a breadboarding-friendly 3-pin 0.1" spacing pin header on the other side?
 
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manie

Senior Member
Also, in ZAR terms, it is just not cheap enough. By the time shipping is done from the USA it becomes very expensive. From Rev-Ed I can get the Axe027 plus some Axes etc on the same shipping cost. Nah, don't think I'll use it.......
 
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BeanieBots

Moderator
Looks far more fiddly and actually more expensive after you've bought the required interface cables than an AXE027.
IMHO only added value (at the expense of convienience) are the 'blinky' LEDs.:rolleyes:
 
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BeanieBots

Moderator
Yes, an Interesting read Martin.
I too am quite sure the device fundamentally works but probably more prone to "getting it wrong" with extra leads and the like.
 
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westaust55

Moderator
womai said:
. . .to use it with a Picaxe not only will you need a USB cable (chances are everybody already has a suitable one from his/her mp3 player or digital camera) . . .
Click to expand...
Well yes, if you have an iPod, a Rivers MP3 players, an Olympus Camera, a Pentax camera and a Canon Camera , etc (yes all are USB to a completely different plug on the device end) then there is a chance one might fit.

I think I will Blinkin’ well live with an AXE027.
I can always put LED’s on my protoboard or breadboard if I need them. :eek:
 
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boriz

Senior Member
I ALWAYS put a LED on serial out / output 0 on the breadboard. Standard practice. I use a LED with resistor soldered inline with one of the legs for convenience.

Every time I put a new Picaxe on the breadboard, I also put the LED on OP0. The first program I run flashes the LED to confirm operation. And it indicates comms with the PC.
 
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BeanieBots

Moderator
I've never felt that 3 wires and two resistors was complex enough to warrant it's own dedicated diagnostics indicator.
Still, nice to know not everyone is a penny pincher and does include the extras. Hope that goes for decoupling caps as well.
 
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boriz

Senior Member
Err...

Actually no.

Any project that makes it off the breadboard will get the full decoupling treatment. But I figure, why not experiment without first. It's easy enough to add caps if I'm having problems, and I have the 'scopes to monitor ripples and such. I'd rather KNOW what needs decoupling and why at the early design stages.
 
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BeanieBots

Moderator
As long as you KNOW then all is fine.

For those that don't, even the cheapest boards from China have decoupling caps for every logic chip that has internal switching so I guess they must KNOW something!

Shame it's not easy to fabricate caps on the die, then every chip (that requires them) could have them built in. Then we could even have regulators which make power supplies without the need for extra components;)

PS. Knowing at the early design stage means reading the datasheet and using a calculator, not trying without and seeing if it works.
 
hippy

hippy

Ex-Staff (retired)
I'm a firm believer in diagnostic LED's for everything. Particularly a power LED to help stop removal or insertion of chips and connecting of wires when powered-up, and I find Serial In and Out LED's to be great for seeing that comms with the PC is working. That's especially useful if you have a system of multiple PICAXE's and you've forgotten to move the cable to the one you are meant to be using ! Anything which quickly narrows down what a problem may be is useful when it's needed.

For power indication, I'll usually have a front panel LED plus LED's on each board. If a mains powered unit I'll usually fit a neon ( often inside the case ) so it's obvious when mains power is connected.
 
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westaust55

Moderator
capcitors and their uses

nbw said:
Decoupling caps?!?!? ;-)
Click to expand...
There are a couple of primary purposes for capacitors in a PICAXE digital world (and yes, audio and other fields have added uses as well).

1. Typically ceramic or polyester type capacitor are used to help filter out higher frequency spikes caused by the switching of transistors within the ICs. Often called a decoupling capacitor.


2. Electrolytic (aluminium can) and Tantalum type capacitors acts as a reserve to help stabilise the voltage where the battery alone might dip in voltage with the load surge. This dips could cause the PICAXE to reset and thus you project would not world as wanted.

For some further information this is a good place to start:
http://www.interfacebus.com/Design_Capacitors.html#d
 
K

kewakl

Senior Member
I used to work with machines that used caps and op-amps to detect/sample/hold the out-of-balance vectors of motor armatures.
They were getting flakey at the end of their lifetimes. (NO wonder!)
 
A

axcampbell

New Member
I use the microusb from sparkfun that plugs directly into your USB port by its edge. All you need then is the 2 resistors and a 4 pin header on the board to program your chips. I found this to be a necessity when I went surface mount as it saves a lot of board real estate.
 
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Andrew Cowan

Senior Member
Or you can use the two resistors and a 3 pin header for theserial connection. Even less board space used! I have an adaptor for three pin header to stereo socket.

A
 
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nbw

Senior Member
Originally Posted by nbw View Post
Decoupling caps?!?!? ;-)

Yeah I know :) It amazes me that more people don't know why these little fellows are so useful / necessary in reliable-izing their circuits.
 
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pha555

Senior Member
I think the intent of the Sparkfun device is USB to 3-term stereo. Unfortunately, I believe the gender of the stereo connector is wrong. It is a socket and should be a plug.

I have a similar item at;

http://www.phanderson.com/picaxe/

Most users use a 6-pin header to directly interface with a solderless breadboard. While tethered to a PC, it provides a source of +5 VDC as well as the download function.

Peter Anderson
 
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