IO Port Pins

[cwarlich]

Hallo,

ich möchte meine FB 7240 zum Steuern und Regeln einsetzen. Kann mir jemand einen Hinweis geben, welcher der vielen FB-Anschlüsse sich eignet, um als simper digitaler IO-Port zweckentfremdet zu werden? Ich brauche mindestens zwei Outputs und einen Input.

Am liebsten würde ich den DSl-Anschluß verwenden, da ich den sowieso nicht brauche und er bei jeder FB vorhanden ist. Aber auch die analogen Telefonanschlüsse der 7240 wären ok. Und wenn es sein muss, kann ich auch in der Box was anlöten, z.B. an die LEDs (nur Outputs?!) oder, falls bei der 7240 vorhanden, an eine serielle Schnittstelle.

Ich bin für jede Hilfe dankbar, und wenn es nur ein Link auf's Datenblatt eines in der 7240 eingesetzten Schnittstellenbausteins ist.

Viele Grüße,

Chris

 

[M66B]

You could try to use an USB to serial converter based on a FTDI chip, for example this one. These chips have some extra I/O lines you can use with a little programming. Freetz includes a FTDI driver and if you like I have some code to interface with this chip. I have never done this for a AVM Fritz!Box but I think this should work.

 

[cwarlich]

That sounds like a viable solution, thanks. Two further questions though:

1) The FTDI boards that I found so far seem to supply the input pins RxD and CTS and the output pins TxD and RTS. Will I be able to fully contol each of these pins individually through USB?
2) I'm particularly concerned w.r.t. RxD and TxD: Is it also possible for these pins to nail them to a fixed logic level through the USB interface?
3) Will other FTDI boards supply additional IO pins?

Thanks for your offering example code, I'm very interested.

 

[M66B]

If you look at the data sheet of the example board (see link in my previous post), you can see there are 4 extra TTL level in/outputs (named CBUS0..3), besides the standard RS232 I/O lines. The state of these lines (in/output and output level) can fully be controlled. Beware that not all FTDI chips can do this, so if you want to find a suitable board, you have to know what FTDI chip is being used on the board, look at the specifications of the chip and check if the board has connected them to a pin header. Another thing to keep in mind is that the speed is limited (but quite fast), so you have to check if the speed is high enough for your application.

Attached is some rudimentary test code I wrote for decoding the signal of a wireless alarm system. Basically it works, but the signal was to noisy to be decoded properly. It is all not very difficult, but it can save you the time of finding out how to do it.

Anhang anzeigen rts.c.zip

 

[cwarlich]

I see. Again, thanks for your help and for your example code!

 

[M66B]

Because I was curious if it would really work on Freetz and I had an unused evaluation board I have tried it and it works perfectly! I have documented here in the wiki how to do it.

Since there was no separate section for libraries, I have included it in the packages list. I hope this is not a problem, else somebody has to help move the wiki page somewhere else.

 

[cwarlich]

Many thanks for taking the time to document this! It is going to make the start of my project just a breeze.

 

[olistudent]

Hm, you missed the starting point for libs... http://freetz.org/wiki/libs

Regards
Oliver

 

[M66B]

I have moved the new wiki page here.
Can somebody delete this page, please?