[Coco] CoCo 1&2 clock cycle events (CPU, SAM, VDG interaction with RAM)

[Darren A]

On 5/24/10, Fedor Steeman wrote:
> Hi all,
>
> Another thing about this clock cycle I cannot seem to figure out is the
> duration. How long does one clock cycle take?
>
> As the 6809 (normally) operates at 0.89 MHz, I can calculate the duration of
> a single E-clock wave (i.e. rise and fall), ought to be 1124 nanoseconds.
>
> According to the reference manual, however, the duration is apparantly 1117
> nanoseconds:
>
> http://www.bighole.nl/pub/mirror/homepage.ntlworld.com/kryten_droid/coco/coco_tm_18.png
> (actually there is a typo, as it says '117')


The 'standard' CoCo CPU speed is 0.89488625 MHz which corresponds to a
1117.4604594 nanosecond cycle time.

Darren