uCAsterisk / Asterisk over AT91SAM9260


We are a designing a 128-port EPABX (non-IP/pure TDM) based on AT91SAM9260. We are planning to port (uC)Linux + (uC)Asterisk over it.

We have a separate DSP to off-load all MIPS intensive threads of Asterisk.

AT91SAM9260 would basicaly be required only for call switching & configuration. Apart from Asterisk, there would also be a HTTP server running along-with to aid configuration of the system.

I need help in making the fwg. choice:

  1. uCAsterisk / Asterisk: Will the MIPS available with AT91SAM9260 sufficient enough to run the above mentioned applns. i.e.
    a) Asterisk (call manager) + HTTP server over Linux (Preferred choice)
    b) uCAsterisk (call manager) + HTTP server over uCLinux.

Plz. suggest the appropriate choice in terms of MIPS required, (a) would have been a preferable choice if it could work.


  1. Has anyone ported uCAsterisk over AT91SAM9260 ?


Hi John

Here are my initial thoughts on the subject:

The AT91SAM9260 is equipped with a MMU as far as I know.
This means you can use real Linux instead of uClinux.
From experience I know that debugging can be much simpler with an MMU equipped CPU compared to non-MMU.
So I would go for “standard” Linux instead of ucLinux, unless you have specific reasons not to.

The SAM9260 is approx. 180 MIPS, again, correct me if I am wrong.
What is the interrupt loading from the DSP ?
Maximum latency allowed to service the DSP in ms ? Will the audio break if interrupt service is e.g. delayed for 1 ms ?

What will the audio path look like ? Everything offloaded to DSP during normal calls ?
What about IVR, voice mail etc. Will that come from the ARM ?

  • Peter