Computing the peripheral clock frequency

[lephe Profile]

Hello there

I'd like to find out the period of the peripheral clock to set up precisely a timer. Of course this will depend on many parameters. I plan to compute this at runtime, for several reasons. I will need to do this on both SH7705 and SH7305, but for now I'm focusing on SH7305.

I'm not familiar enough with electronics to fully understand the block diagram of the clock pulse generator (at page 588 in the SH7724 documentation). I would think the vertical lines which are connected to MD0, MD1, MD2 represent possible alternatives that depend on the clock mode. Is it right ?

If I understand correctly, I would need to take the following parameters into consideration:
- clock mode (influences everything)
- FLL multiplication
- PLL multiplication
- Divider 1 (FRQCRA)

I'm not sure I fully understand how it works. Am I right regarding the circuit structure ? Is there any common way of computing this frequency ?

Regards,
lephe