Is the Audio Jack required? First time User

C

Cillakin

Member
Hello friends! I want to buy picaxe microcontrollers to do a lot of projects I have in mind. But there is a problem that I cannot find a solution to on the WWW or datasheets/manuals or YouTube etc. The problem is I cannot get a definitive answer to a question I have. Why do all kits and chips use an audio jack, i think 3.5mm or so? I am not unfamiliar to serial connections, USB, etc. I have an FTDI FT232R chip I want to use to convert to USB/Serial. I found a guy on youtube who used FTDI chip and Hex inverter to get the signals on the same page.

If all you need is the right sequencing on data and the Tx/Rx/GND then why use a part that is not something i have or plan on using? Can I ditch the audio jack and just use the hex inverter/ft232r?

Thank you all!
 
C

Cillakin

Member
Another thought came to me and I am not 100% sure if it will work, but my brain says it will. So here goes...

I purchased a PICKit 3 IDE from my local electronics warehouse a little while back. The product can be viewed here. There is also an eBay listing for it here. As long as I don't use the ICSP from the PICKit 3 and just use the RJ-11 to USB hookup, it should work exactly the same as any other IDE for PICAXE. Since you connect what pins to what header you want via the ZIF socket, it doesn't seem like it would be a problem because I think U1 in their schematic-ish chart is a serial converter of some kind. It doesn't look like an FT232R/Q. I'll have to go look closer at it later on.

So with that being said, I think it will work just fine given it's a PIC IDE, and after all, PICAXE's are PIC's with some chest hair after all. So if it can program using the same type of TTL as the PIC, then the PICAXE should program too, yes? Thank you friends again for any help you can provide me with. I greatly appreciate the it! :)
 
J

Jeremy Harris

Senior Member
The 3.5mm stereo jack is used, I think just because it's a cheap and robust connector that survives well in an educational environment. As long as you follow the connection circuit diagram shown in the Picaxe manual, with the 22k and 10k resistors to protect the serial input pin, then you can use any sort of connector you like. I commonly use a simple three pin header with an adaptor to the Picaxe serial programming lead (just three wires going to a flying 3.5mm socket). You can use other USB to serial converters to programme the Picaxe, BUT there have been issues reported with some of them. The Picaxe Programming Editor and the USB to serial driver are slightly fussy about the actual chip used in the interface, I believe, and some of the Chinese clone USB to serial converters may not work (I think the general consensus is that most do).
 
C

Cillakin

Member
Jeremy Harris said:
The 3.5mm stereo jack is used, I think just because it's a cheap and robust connector that survives well in an educational environment. As long as you follow the connection circuit diagram shown in the Picaxe manual, with the 22k and 10k resistors to protect the serial input pin, then you can use any sort of connector you like.
Click to expand...

Does this imply that the audio jack is used to side-step the resistors? Does the jack have some type of internal resistance? I seriously doubt that but hey, there's cool stuff out there so why not?:rolleyes:


Jeremy Harris said:
I commonly use a simple three pin header with an adaptor to the Picaxe serial programming lead (just three wires going to a flying 3.5mm socket).
Click to expand...
So something to the effect of a servo motor cable?

Jeremy Harris said:
You can use other USB to serial converters to programme the Picaxe, BUT there have been issues reported with some of them. The Picaxe Programming Editor and the USB to serial driver are slightly fussy about the actual chip used in the interface, I believe, and some of the Chinese clone USB to serial converters may not work (I think the general consensus is that most do).
Click to expand...
I've had issues with Atmel chips before, and with any other IC to be honest. I suppose if it doesn't work just hit 'retry' and hope for the best?

I'd really like to save some money and just buy a nice cheap MCU. As opposed to an IDE, MCU, Adapter, etc. It adds up especially since i have what appears to be perfectly functional hardware for this platform and it's parent platform. :p
 
C

Cillakin

Member
manuka said:
Cillakin: Rest easy - the PICAXE 3 wire programming requirement is nothing smart. Such skinflints as us down-under Kiwis in fact prefer simple PCB header pin versions that insert into a solderless breadboard.

A USB-serial cable however is needed, for which I recommend robust but dirt cheap Chinese "blue" offerings. I've bought crates of these to great effect, & they always work a treat (once drivers are loaded). Stan.
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I ended up just saying to heck with it, bought the FTDI Cable at Sparkfun. I'm going to flash the FT232R so it will work as it is, no extra hardware such as the hex inverter. I'll attempt to use my PIC IDE board to program a PICAXE (obviously no programming with PICKit 3) with just the IDE board and the RJ-11 to USB cable. I think it will work. But I did have doubts, so I bought extra PICAXE chips.
 
M

manuka

Senior Member
Ok - but don't make things too hard for yourself! PICAXE programming needs near trivial hardware. I have never needed to add hex inverters in my ~10 years of personal & supervisory progarmming either!

Note - PICAXEs are not plain PICs, since Rev.Ed has already added smarts to them for interpreting user friendly high level commands. I trust you realise the (free) PICAXE Editor is normally needed for PICAXE programming?
 
M

MikeAusP

Member
Cillakin said:
. . . . If all you need is the right sequencing on data and the Tx/Rx/GND then why use a part that is not something i have or plan on using? Can I ditch the audio jack and just use the hex inverter/ft232r? . . . . .
Click to expand...
Yes, all you need is the right sequencing of Data on Tx/Rx/Gnd leads. The standard used for this on every PICAXE board is the 3.5mm Connector (the same connector that's used for Stereo Audio on many devices).

But on PICAXEs it's not used for Audio - it's used for Serial Data and can be directly connected to PC Serial ports.

The interface between the PC Serial port and any PICAXE only needs two resistors - RevEd couldn't have made it any simpler - why not just use it.

The Audio jack is a Connector and Hex Inverter/Ft232R are electronics - how can anyone answer that question ???
 
Hemi345

Hemi345

Senior Member
Cillikin, see page 44 of PICAXE manual 1. That 3 pin header is what I use on all my boards.
 
C

Cillakin

Member
Hemi345 said:
Cillikin, see page 44 of PICAXE manual 1. That 3 pin header is what I use on all my boards.
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Perfect! Thanks a bunch. I'll look at that and plan around it, although given it's just a 3 pin header, I doubt it could get any simpler than that.

As for why use the FT232R and inverter is because I do not have any serial ports in my laptop or my wife's laptop. She has a DB15 port, making the serial output/cord pretty much useless. There's also incentive to get in on the same level as every other project I have. USB is the go-to port for all of my projects, or a DC Jack. Since I don't need the jack I just need the USB for programming of the PICAXE.

Thanks again everyone for the input! I did get the FT232R USB Programmer from sparkfun, so that should get everything in order. I plan on removing the Audio jack and putting in headers as I do not have any stereo/audio cables to interface with the audio jack. Yes, an audio jack is simple, no doubt. But it's not what I want to use, and it's something I don't use or plan on using unless the project is specifically audio.

The community is great here, this was a huge buying/selling point for me in using the PICAXE. It's got a much more robust community than PIC or even Arduino I suppose. And Parralax Propeller chips, well, not a lot going on there as far as I could tell. Thank again everyone, you've been a great help.
 
L

lewisg

Senior Member
Cillakin said:
Can I ditch the audio jack...
Click to expand...
Sure, all you need is three chords and the truth... Whoops, that's songwriting.

I thought the 1/8" stereo jack was the dumbest thing I'd ever seen when I started with Picaxe. All my early projects had three pin headers. Had some problems with reliability when hooking into installed projects in the field and began to see the wisdom of the "audio jack" interface. Now since my laptop has NO serial port and I have to use USB (an interface that makes SCSI look good) I seriously recommend getting a AXE027 cable and sticking to the 1/8" stereo interface. Why screw around?
 
C

Cillakin

Member
lewisg said:
Sure, all you need is three chords and the truth... Whoops, that's songwriting.

I thought the 1/8" stereo jack was the dumbest thing I'd ever seen when I started with Picaxe. All my early projects had three pin headers. Had some problems with reliability when hooking into installed projects in the field and began to see the wisdom of the "audio jack" interface. Now since my laptop has NO serial port and I have to use USB (an interface that makes SCSI look good) I seriously recommend getting a AXE027 cable and sticking to the 1/8" stereo interface. Why screw around?
Click to expand...
Because it's a nice chunk of change for that AXE027 cable. I'd also prefer to build my own since its much cheaper, hence the FT232R. If all else fails I'll get the cable, but in the meantime I'll give this a go. I'm also anxious to see how it works with Ubuntu 13.04. I'm not an Apple or Windows kind of guy. Free is the way to go for a computer.

It does appear the audio jack is a more simple design, which is I'm sure why they went with it. Complexity has it's price...
 
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