Do you need a KEY

SailerMan

Is there another way to program the SX without using a key? Say I want to make a module and all you have to do is attach a USB cable to program the SX.

Is there a proven circuit besides that of the SXkey that will work?

Thanks,
Eric

Bean

If you want to use the SX-Key IDE software then you'll have to use either the SX-Key or the SX-Blitz.
If you are just using it to program then the SX-Blitz is much cheaper, and it's USB.
The easiest thing would be to just mount the SX-Blitz to your board.

Bean.

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SailerMan

OK thanks.

Eric

LoopyByteloose

Though the SXes are very similar to the PICs in much of the concept, there was a large divergence in philosophy when it came to the programng port. As I recall the PIC allows a programing entry through a couple fo general purpose piin, but the SXes use the oscillator pins as the programing port.

I suspect the SXes wanted to make the programing port more secure [noparse][[/noparse]no possiblity of remote reprograming] while allowing more pins to be available for more functions. After all, the SXes had greatly faster speed and twice the memory than their PIC counterparts.

There was an effort to have a generic DIY clone of the SX-Key - it is called Fluffy2 - but it requires a PIC microcontroller that essentially doubles the chip count and cost of a board. AND, you still cannot operate the SX without physically disconnecting the programing interface and installing a resonator or crystal.

The SX-Key has several goodies, but Parallax also produced the SX-Blitz as a low cost 'student' version. Since the SX-Blitz is so reasonable, there really in little reason to build a Fluffy2 unless you are a die hard DIYer.

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"Everything in the world is purchased by labour; and our passions are the only causes of labor." -- David·Hume (1711-76)········

···················· Tropically,····· G. Herzog [noparse][[/noparse]·黃鶴 ]·in Taiwan

Steel

I could be wrong in this...but the Download communication spec is outlined in the SX User manual, isn't it?

And isn't the SX/Key just an SX taking UART data from the FTDI Chip, and translating it into the OSC1/OSC2 pin toggles?

This should be a very easy thing to do, shouldn't it?· It isn't any different than programming any other code.

Debugging, I can see some hardships...But just for programming it should be relatively simple..

Guenther Daubach

The most important reason why the OSC1/OSC2 pins are used for serial programming and debugging is not to make the programming port more secure. Those two pins are the only ones that can be disconnected in a target system without influencing any other function. If some I/O pins would be used for this purpose (like in the parallel programming mode), they could not be used for general I/O.

Programming the SX is not just a matter of simply taking the UART data from the FTDI chip, and translating it into OSC1/2 toggles. You can find more information about chip programming here:

www.parallax.com/dl/docs/prod/sx/DeviceProgramming.pdf

If you look at the SX-Blitz USB, besides the FTDI chip you will also find an SX20 plus a bunch of other components. The SX20 handles the communication between the PC and the SX-Blitz, and it also handles the programming communications with the SX on the target system. It is also is used to generate the programming voltage Vpp (about 12V) that is required. On the SX-Key, you will also find a clock generator chip that is required to provide clock frequency you have selected for the target system. For debugging, it is also necessary that a little utility program is loaded into the target SX. The SX-Key automatically does this when you program an SX device for debugging in order to handle the debugging communication with the SX-Key IDE.

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Greetings from Germany,

G

LoopyByteloose

Considering all the support, examples, and free docs that Parallax provides, it really difficult to begrudge them this profit center.

In addition, they do it so well. The SX-Key allows you to test with different frequency clocks to make sure your timing expectations are met.

Nonetheless, I feel that having the Fluffy to look at gives you an educational reference. I printed one of the Fluffy boards, but never bothered to populate it. It is just another building task to divert me from building more significant projects.

The only think I had done is to add a bit of flexible cable from the SX-Key to the actual Board [noparse][[/noparse]I used a 10 wire ribbon cable]. This prevents me damaging the board or the SX-Key due to rigidity of the connection. I suppose that it may give me oscillator emulation troubles sometime, but it seems okay for programing.

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"Everything in the world is purchased by labour; and our passions are the only causes of labor." -- David·Hume (1711-76)········

···················· Tropically,····· G. Herzog [noparse][[/noparse]·黃鶴 ]·in Taiwan