Generate AX. 25 Modem signals with a PIC.

[Pic Toy]

Hi All,

Can you please help me to generate AX 25 protocol with a PIC.

How do you generate the 1200 Hz and 2200 Hz frequencies and the data out on a port with R2R ladder on 4 bits?

I am busy building a Packet Radio modem for HAM use. Packet Radio / APRS Transmissions.

I am a licenced Radio HAM and use PBP.

Thanks my Friends

Pic Toy

[skimask]

Hi All,
Can you please help me to generate AX 25 protocol with a PIC.
How do you generate the 1200 Hz and 2200 Hz frequencies and the data out on a port with R2R ladder on 4 bits?
I am busy building a Packet Radio modem for HAM use. Packet Radio / APRS Transmissions.
I am a licenced Radio HAM and use PBP.
Thanks my Friends
Pic Toy

FREQOUT...it's all in the manual...but then that's only a one-bit output. Put a filter on the output that's good enough and you shouldn't need a 4 bit ladder...

(Yep...I said it...the manual...unless of course you don't have a manual...)

[Pic Toy]

Hi Skimask,

Thanks for your reply. I have used Freqout in the past to create tones with the simple filter , but how do I convert serial data into an audio signal, D-A conversion? not sure what and how to send it to 4 bits on eg. PortB.0 to PortB.3 with R2R D-A?

I bought PBP many years back from MeLabs and updates from local distributor.

BR
Pic Toy

[skimask]

Hi Skimask,

Thanks for your reply. I have used Freqout in the past to create tones with the simple filter , but how do I convert serial data into an audio signal, D-A conversion? not sure what and how to send it to 4 bits on eg. PortB.0 to PortB.3 with R2R D-A?

I bought PBP many years back from MeLabs and updates from local distributor.

BR
Pic Toy

XR2206?

I just looked at the spec's for AX.25...
Good luck with that...

[Pic Toy]

Yes I can use the XR2206 or even the FX604 or FX614, guys are doing it all with one single 16F84 and 16F628.

BR
Pic Toy

[skimask]

Yes I can use the XR2206 or even the FX604 or FX614, guys are doing it all with one single 16F84 and 16F628.

BR
Pic Toy

So what you're saying is...(gotta see if I'm getting this right or not)...

A serial line input....regular ol' RS232 type serial data type stuff...

4 bit ladder output....Port D0-D3 for example...

Serial input is low, output on 4 bit ladder is effectively a 'sine' wave at 1200hz...
Serial input is high, output on 4 bit ladder is a 'sine' wave at 2200hz?

Standard ol' Bell202 (was it the 202?) modem type stuff yes?