Lpc2000

--- In lpc2000@yahoogroups.com, "jamesasteres" <jamesasteres@y...> 
wrote:
> 
> The CAN samples provied by Embedded Systems Academy are awesome, 
> thank you!  But, can anyone explain the meaning of bit timing?  I 
> know this has been discussed before but for the life of me it is 
> confusing.  The User Manual is especially terse, just listing 
> the "baud rate prescaler" in CANBTR register.  I notice in the 
> samples the prescaler value is 0x1D which gives a divisor of 30.  
On 
> a 60 Mhz VPCLK this would give 60 / 30 = 2 Mhz baud rate.  Is this 
> correct?  I feel I must be missing something.
> James

The CAN bit timing is confusing to the uninitiated. The divisor 
selects the time for tq (the time quantum if I recall correctly). 
There are many tqs to the actual bit period. A typical number would 
be 8 tqs per bit period but this is dependent on various factors.

Have a look at http://www.kvaser.com/can/protocol/canbit.htm.