CANBUS: SJA1000 talks to MICROCHIP

That's not exactly the information needed to define a CAN bus bit timing. What are the clock dividers for each of those devices, i.e. what's the time quantum? And what _are_ the actual settings on each type of node? (N_TSEG1, N_TSEG2, N_SJW, others?)

That's a strange way to set up things, indeed. Are you sure you're reading the PIC's datasheet correctly regarding the meaning of that setting?

The actual propagation time, t_PROP is not even a controllable parameter of the definition of the actual bit timing in the first place. It's a limit set by the transceivers and cabling that the bit timing must be designed to obey:

t_PROP < (N_TSEG1 + 1 - 25 * (N_TSEG1 + N_TSEG2 + 1) * \delta(t_q)) * t_q

Note that this includes \delta(t_q), the error of the time quantum length due to clock variations. That's a rather volatile parameter not really under control of the uC, so I really don't see you could ever deduce values for N_TSEG1 or N_TSEG2 from a set value for t_PROP.

And rightly so, I'd say...