[Tinyos-help] backoff and transmissions retries in CC2420Transmit

[Erwing R. Sanchez]

Hi,
I've been looking at the CC2420Transmit component and have some  
questions.
First, I would like to know what are the units of the backoff time;  
some comments in the code simply indicate that it is unknown, but I  
guess that since the timer used to measure the backoff is a 32khz- 
based timer, then the units should be in 1/32k. This is correct?
According the code, when a packet is going to be sent the radio backs  
off for an 'InitialBackoff' amount of time; after that, the channel  
is sensed and if it is free then another amount of time equals to  
'CC2420_ack_turnaround_time' is waited before really attempting to  
send the package. Is this interpretation correct?
Finally, I would like to know how many attempts to send a message are  
performed if the channel is busy; by looking at the code, it seems  
that there are not bounds and that infinite transmission retries will  
be performed if upper layers don't stop them. Am I right?
Thanks for your help.
Erwing