Timers

From my tests it seems all 3 timer modules are equal (the fast timer, the first timer, and the second timer), but the fast timer has a special register set to 0x0. This register is not in a standard sp804. It’s at offset 0x80 from the timer base address. It is some sort of clock selection register. If the first bit is set, it uses a ~10MHz clock. The second bit overrules the first one. If it is set, a 32kHz clock is used. If neither bit is set, a 33MHz clock is used. At this time, I have only tested values from 0 to 0xff and all single bits, for the fast timer and the second timer. And only on my hardware, a CX CAS HW-AA. Firebird only supports the 32kHz clock at this time.

- nspiredev500