] Officially there is the CLOCK signal (pin42) and it should be 3.58MHz.
] (Even on Turbo-R in R800 mode the CLOCK signal is 3.58MHz, can someone
] confirm this?
Yes, it is 3.58Mhz indeed.
] What about the read/write cycles, are these at 3.58MHz
] too?
Yes. The S1990 makes sure that Z80 timing is used for read/write to cartridge
slots.
] then R800 has no use when programcode is running in an external
] mapper?!)
It still has use, since only fetching the instructions is slowed down to Z80
speed. The execution of the instructions is still done at R800 speed. But you
are partly right. When executing cartridge programs the R800 is on the
average only twice as fast as a normal MSX. For programs executed from the
internal memory, the R800 is on the average 5 to 6 times as fast as a normal
MSX. Though, in theory it can be up to 10 times as fast. And when using the
special multiplication functions in programs with lots of integer
calculations the speed-up can even be larger.
Kind regards,
Alex Wulms
--
Alex Wulms/XelaSoft - MSX of anders NIX - Linux 4 ever
See my homepage for info on the *** XSA *** format
http://www.inter.nl.net/users/A.P.Wulms
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